Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 120
Filter
1.
J Neurochem ; 160(3): 325-341, 2022 02.
Article in English | MEDLINE | ID: mdl-34878647

ABSTRACT

The nucleus accumbens (NAc) plays critical roles in emotional behaviors, including aversive learning. Aversive stimuli such as an electric foot shock increase acetylcholine (ACh) in the NAc, and muscarinic signaling appears to increase neuronal excitability and aversive learning. Muscarinic signaling inhibits the voltage-dependent potassium KCNQ current which regulates neuronal excitability, but the regulatory mechanism has not been fully elucidated. Phosphorylation of KCNQ2 at threonine 217 (T217) and its inhibitory effect on channel activity were predicted. However, whether and how muscarinic signaling phosphorylates KCNQ2 in vivo remains unclear. Here, we found that PKC directly phosphorylated KCNQ2 at T217 in vitro. Carbachol and a muscarinic M1 receptor (M1R) agonist facilitated KCNQ2 phosphorylation at T217 in NAc/striatum slices in a PKC-dependent manner. Systemic administration of the cholinesterase inhibitor donepezil, which is commonly used to treat dementia, and electric foot shock to mice induced the phosphorylation of KCNQ2 at T217 in the NAc, whereas phosphorylation was suppressed by an M1R antagonist. Conditional deletion of Kcnq2 in the NAc enhanced electric foot shock induced aversive learning. Our findings indicate that muscarinic signaling induces the phosphorylation of KCNQ2 at T217 via PKC activation for aversive learning.


Subject(s)
Avoidance Learning/physiology , KCNQ2 Potassium Channel/metabolism , Nerve Tissue Proteins/metabolism , Nucleus Accumbens/metabolism , Parasympathetic Nervous System/physiology , Protein Kinase C/metabolism , Receptors, Muscarinic/physiology , Animals , Carbachol/pharmacology , Cholinesterase Inhibitors/pharmacology , Donepezil/pharmacology , KCNQ2 Potassium Channel/genetics , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Muscarinic Agonists/pharmacology , Muscarinic Antagonists/pharmacology , Nerve Tissue Proteins/genetics , Phosphorylation , Receptor, Muscarinic M2/drug effects
2.
J Neurochem ; 160(3): 342-355, 2022 02.
Article in English | MEDLINE | ID: mdl-34878648

ABSTRACT

Cholinergic transmission underlies higher brain functions such as cognition and movement. To elucidate the process whereby acetylcholine (ACh) release is maintained and regulated in the central nervous system, uptake of [3 H]choline and subsequent synthesis and release of [3 H]ACh were investigated in rat striatal segments. Incubation with [3 H]choline elicited efficient uptake via high-affinity choline transporter-1, resulting in accumulation of [3 H]choline and [3 H]ACh. However, following inhibition of ACh esterase (AChE), incubation with [3 H]choline led predominantly to the accumulation of [3 H]ACh. Electrical stimulation and KCl depolarization selectively released [3 H]ACh but not [3 H]choline. [3 H]ACh release gradually declined upon repetitive stimulation, whereas the release was reproducible under inhibition of AChE. [3 H]ACh release was abolished after treatment with vesamicol, an inhibitor of vesicular ACh transporter. These results suggest that releasable ACh is continually replenished from the cytosol to releasable pools of cholinergic vesicles to maintain cholinergic transmission. [3 H]ACh release evoked by electrical stimulation was abolished by tetrodotoxin, but that induced by KCl was largely resistant. ACh release was Ca2+ dependent and exhibited slightly different sensitivities to N- and P-type Ca2+ channel toxins (ω-conotoxin GVIA and ω-agatoxin IVA, respectively) between both stimuli. [3 H]ACh release was negatively regulated by M2 muscarinic and D2 dopaminergic receptors. The present results suggest that inhibition of AChE within cholinergic neurons and of presynaptic negative regulation of ACh release contributes to maintenance and facilitation of cholinergic transmission, providing a potentially useful clue for the development of therapies for cholinergic dysfunction-associated disorders, in addition to inhibition of synaptic cleft AChE.


Subject(s)
Acetylcholine/biosynthesis , Neostriatum/metabolism , Acetylcholinesterase/metabolism , Animals , Calcium Channel Blockers/pharmacology , Choline/metabolism , Cholinesterase Inhibitors/pharmacology , Electric Stimulation , Male , Potassium Chloride/pharmacology , Radiopharmaceuticals , Rats , Rats, Wistar , Receptor, Muscarinic M2/drug effects , Receptor, Muscarinic M2/metabolism , Receptors, Dopamine D1/drug effects , Receptors, Dopamine D1/metabolism , Vesicular Acetylcholine Transport Proteins/antagonists & inhibitors , Vesicular Acetylcholine Transport Proteins/metabolism
3.
Clin Immunol ; 212: 108346, 2020 03.
Article in English | MEDLINE | ID: mdl-31954803

ABSTRACT

Previous studies showed that circulating autoantibodies against M2 muscarinic receptors (anti-M2R Ab) are associated with decreased cardiac parasympathetic modulation in patients with chronic Chagas disease (CD). Here we investigated whether the exposure of M2R to such antibodies could impair agonist-induced receptor activation, leading to the inhibition of associated signaling pathways. Preincubation of M2R-expressing HEK 293T cells with serum IgG fractions from chagasic patients with cardiovascular dysautonomia, followed by the addition of carbachol, resulted in the attenuation of agonist-induced Gi protein activation and arrestin-2 recruitment. These effects were not mimicked by the corresponding Fab fractions, suggesting that they occur through receptor crosslinking. IgG autoantibodies did not enhance M2R/arrestin interaction or promote M2R internalization, suggesting that their inhibitory effects are not likely a result of short-term receptor regulation. Rather, these immunoglobulins could function as negative allosteric modulators of acetylcholine-mediated responses, thereby contributing to the development of parasympathetic dysfunction in patients with CD.


Subject(s)
Autoantibodies/immunology , Autonomic Nervous System Diseases/immunology , Chagas Disease/immunology , Receptor, Muscarinic M2/immunology , Adult , Aged , Allosteric Regulation , Autoantibodies/metabolism , Autoantibodies/pharmacology , Autonomic Nervous System Diseases/etiology , Autonomic Nervous System Diseases/metabolism , Autonomic Nervous System Diseases/physiopathology , Carbachol/pharmacology , Chagas Disease/complications , Chagas Disease/metabolism , Chagas Disease/physiopathology , Cholinergic Agonists/pharmacology , Female , GTP-Binding Protein alpha Subunits, Gi-Go/metabolism , GTP-Binding Protein alpha Subunits, Gq-G11/metabolism , HEK293 Cells , Heart Rate , Humans , Male , Middle Aged , Receptor, Muscarinic M2/drug effects , Receptor, Muscarinic M2/metabolism , beta-Arrestin 1/metabolism
4.
Neuropharmacology ; 162: 107828, 2020 01 01.
Article in English | MEDLINE | ID: mdl-31654703

ABSTRACT

Cholinergic dysfunction plays a critical role in a number of disease states, and the loss of functional muscarinic acetylcholine receptors plays a key role in disease pathogenesis. Therefore, preventing receptor downregulation would maintain functional receptor number, and be predicted to alleviate symptoms. However, the molecular mechanism(s) underlying muscarinic receptor downregulation are currently unknown. Here we demonstrate that the M2 muscarinic receptor undergoes rapid lysosomal proteolysis, and this lysosomal trafficking is facilitated by ubiquitination of the receptor. Importantly, we show that this trafficking is driven specifically by ESCRT mediated involution. Critically, we provide evidence that disruption of this process leads to a re-routing of the trafficking of the M2 receptor away from the lysosome and into recycling pathway, and eventually back to the plasma membrane. This study is the first to identify the process by which the M2 muscarinic acetylcholine receptor undergoes endocytic sorting, and critically reveals a regulatory checkpoint that represents a target to pharmacologically increase the number of functional muscarinic receptors within the central nervous system.


Subject(s)
Endosomal Sorting Complexes Required for Transport/metabolism , Lysosomes/metabolism , Neurons/metabolism , Receptor, Muscarinic M2/metabolism , Ubiquitin/metabolism , Animals , Carbachol/pharmacology , Cell Membrane/drug effects , Cell Membrane/metabolism , Chloroquine/pharmacology , Cholinergic Agonists/pharmacology , Down-Regulation , Endosomal Sorting Complexes Required for Transport/drug effects , Endosomes/drug effects , Endosomes/metabolism , Endosomes/ultrastructure , Ganglia, Spinal/cytology , Gene Expression Regulation , HEK293 Cells , Humans , Lysosomes/drug effects , Lysosomes/ultrastructure , Microscopy, Confocal , Neurons/drug effects , Neurons/ultrastructure , Protein Transport/drug effects , Proteolysis , Rats , Receptor, Muscarinic M2/drug effects , Receptor, Muscarinic M2/genetics , Transfection , Ubiquitin/drug effects , Ubiquitination
5.
Brain Res Bull ; 144: 14-20, 2019 01.
Article in English | MEDLINE | ID: mdl-30391542

ABSTRACT

Central cholinergic activation stimulates water intake, but also NaCl intake when the inhibitory mechanisms are blocked with injections of moxonidine (α2 adrenergic/imidazoline agonist) into the lateral parabrachial nucleus (LPBN). In the present study, we investigated the involvement of central M1 and M2 muscarinic receptors on NaCl intake induced by pilocarpine (non-selective muscarinic agonist) intraperitoneally combined with moxonidine into the LPBN or by muscimol (GABAA agonist) into the LPBN. Male Holtzman rats with stainless steel cannulas implanted bilaterally in the LPBN and in the lateral ventricle were used. Pirenzepine (M1 muscarinic antagonist, 1 nmol/1 µl) or methoctramine (M2 muscarinic antagonist, 50 nmol/1 µL) injected intracerebroventricularly (i.c.v.) reduced 0.3 M NaCl and water intake in rats treated with pilocarpine (0.1 mg/100 g of body weight) injected intraperitoneally combined with moxonidine (0.5 nmol/0.2 µL) into the LPBN. In rats treated with muscimol (0.5 nmol/0.2 µL) into the LPBN, methoctramine i.c.v. also reduced 0.3 M NaCl and water intake, however, pirenzepine produced no effect. The results suggest that M1 and M2 muscarinic receptors activate central pathways involved in the control of water and sodium intake that are under the influence of the LPBN inhibitory mechanisms.


Subject(s)
Drinking/drug effects , Parabrachial Nucleus/metabolism , Receptor, Muscarinic M1/metabolism , Receptor, Muscarinic M2/metabolism , Sodium Chloride/metabolism , Animals , Diamines/pharmacology , Drinking Behavior/drug effects , Imidazoles/pharmacology , Male , Muscarinic Agonists/pharmacology , Muscarinic Antagonists/pharmacology , Muscimol/pharmacology , Parabrachial Nucleus/drug effects , Pilocarpine/pharmacology , Pirenzepine/pharmacology , Rats , Rats, Sprague-Dawley , Receptor, Muscarinic M1/drug effects , Receptor, Muscarinic M2/drug effects , Sodium, Dietary
6.
Mol Pharmacol ; 94(5): 1298-1309, 2018 11.
Article in English | MEDLINE | ID: mdl-30213802

ABSTRACT

Muscarinic acetylcholine receptors (mAChRs) are exemplar models for understanding G protein-coupled receptor (GPCR) allostery, possessing a "common" allosteric site in an extracellular vestibule (ECV) for synthetic modulators including gallamine, strychnine, and brucine. In addition, there is intriguing evidence of endogenous peptides/proteins that may target this region at the M2 mAChR. A common feature of synthetic and endogenous M2 mAChR negative allosteric modulators (NAMs) is their cationic nature. Using a structure-based approach, we previously designed a mutant M2 mAChR (N410K+T423K) to specifically abrogate binding of ECV cationic modulators (Dror et al., 2013). Herein, we used this "allosteric site-impaired" receptor to investigate allosteric interactions of synthetic modulators as well as basic peptides (poly-l-arginine, endogenously produced protamine, and major basic protein). Using [3H]N-methylscopolamine equilibrium and kinetic binding and functional assays of guanosine 5'-O-[γ-thio]triphosphate [35S] binding and extracellular signal-regulated kinases 1 and 2 phosphorylation, we found modest effects of the mutations on potencies of orthosteric antagonists and an increase in the affinity of the cognate agonist, acetylcholine, likely reflecting the effect of the mutations on the access/egress of these ligands into the orthosteric pocket. More importantly, we noted a significant abrogation in affinity for all synthetic or peptidic modulators at the mutant mAChR, validating their allosteric nature. Collectively, these findings provide evidence for a hitherto-unappreciated role of endogenous cationic peptides interacting allosterically at the M2 mAChR and identify the allosteric site-impaired GPCR as a tool for validating NAM activity as well as a potential candidate for future chemogenetic strategies to understand the physiology of endogenous allosteric substances.


Subject(s)
Cholinergic Agents/pharmacology , Receptor, Muscarinic M2/drug effects , Allosteric Site , Animals , Binding Sites , CHO Cells , Cricetulus , Kinetics , Ligands , Mutation , N-Methylscopolamine/pharmacology , Receptor, Muscarinic M2/genetics , Receptor, Muscarinic M2/metabolism , Reproducibility of Results
7.
Neurourol Urodyn ; 37(8): 2560-2570, 2018 11.
Article in English | MEDLINE | ID: mdl-30252154

ABSTRACT

AIMS: We explored the therapeutic potential of intragastric administration traditional Chinese medicine Glycine tomentella Hayata (I-Tiao-Gung, ITG) extract and its active component Daidzin on cyclophosphamide (CYP)-induced cystitis and bladder hyperactivity in rats. METHODS: Female Wistar rats were divided into control, CYP (200 mg/kg), CYP + ITG (1.17 g/kg/day), CYP + Daidzin (12.5 mg/kg/day), and 1 week of ITG preconditioning with CYP (ITG + CYP) groups. We determined the trans cystometrogram associated with external urethral sphincter electromyogram, and the expression of M2 and M3 muscarinic and P2 × 2 and P2 × 3 purinergic receptors by Western blot in these animals. RESULTS: ITG extract contains 1.07% of Daidzin and 0.77% of Daidzein by high-performance liquid chromatography. Daidzin was more efficient than Daidzein in scavenging H2 O2 activity by a chemiluminescence analyzer. CYP induced higher frequency, shorter intercontraction interval, lower maximal voiding pressure, lower threshold pressure, and Phase-2 emptying contraction with a depressed external urethral sphincter electromyogram activity, and hemorrhagic cystitis in the bladders. The altered parameters by CYP were significantly improved in CYP + ITG, CYP + Daidzin, and ITG + CYP groups. The P2 × 2 and P2 × 3 expressions were significantly upregulated in CYP group, but were depressed in CYP + ITG, CYP + Daidzin, and ITG + CYP groups. The M2 expression was not significantly different among these five groups. The M3 expression was significantly upregulated in CYP group, but was significantly depressed in CYP + ITG, CYP + Daidzin, and ITG + CYP groups. CONCLUSIONS: These data suggest that ITG extract through its active component Daidzin effectively improved CYP-induced cystitis by the action of restoring Phase 2 activity and inhibiting the expressions of P2 × 2, P2 × 3, and M3 receptors.


Subject(s)
Drugs, Chinese Herbal/pharmacology , Isoflavones/pharmacology , Urinary Bladder/drug effects , Animals , Cyclophosphamide/toxicity , Cystitis/chemically induced , Cystitis/physiopathology , Electromyography , Female , Rats , Rats, Wistar , Receptor, Muscarinic M2/drug effects , Receptor, Muscarinic M2/metabolism , Receptor, Muscarinic M3/drug effects , Receptor, Muscarinic M3/metabolism , Receptors, Purinergic P2/drug effects , Receptors, Purinergic P2/metabolism , Urethra/drug effects , Urethra/physiopathology , Urinary Bladder/metabolism , Urinary Bladder/physiopathology , Urinary Bladder, Overactive/chemically induced , Urinary Bladder, Overactive/physiopathology , Urination/drug effects
8.
Biochem Biophys Res Commun ; 496(1): 101-104, 2018 01 29.
Article in English | MEDLINE | ID: mdl-29305262

ABSTRACT

The muscarinic M2 receptor (M2R) has been shown to display voltage-sensitive agonist binding, based on G protein-activated inward rectifier potassium channel (GIRK) opening and radioligand binding at different membrane voltages. A conserved aspartate in transmembrane segment (TM) II of M2R, D69, has been proposed as the voltage sensor. While a recent paper instead presented evidence of tyrosines in TMs III, VI, and VII acting as voltage sensors, these authors were not able to record GIRK channel activation by a D69N mutant M2R. In the present study, we succeeded in recording ACh-induced GIRK channel activation by this mutant at -80 and 0 mV. The acetylcholine EC50 was about 2.5-fold higher at 0 mV, a potency shift very similar to that observed at wild-type M2R, indicating that voltage sensitivity persists at the D69N mutant. Thus, our present observations corroborate the notion that D69 is not responsible for voltage sensitivity of the M2R.


Subject(s)
Acetylcholine/administration & dosage , G Protein-Coupled Inwardly-Rectifying Potassium Channels/metabolism , Membrane Potentials/drug effects , Membrane Potentials/physiology , Receptor, Muscarinic M2/genetics , Receptor, Muscarinic M2/metabolism , Animals , Aspartic Acid/genetics , Cells, Cultured , Conserved Sequence , Dose-Response Relationship, Drug , Mutagenesis, Site-Directed , Oocytes , Point Mutation/genetics , Receptor, Muscarinic M2/drug effects , Structure-Activity Relationship , Xenopus laevis
9.
Mol Pain ; 13: 1744806917710779, 2017.
Article in English | MEDLINE | ID: mdl-28474958

ABSTRACT

Background: Although decanoic acid (DA) is thought to act as a muscarinic cholinergic agonist, effect of DA on nociceptive behavioral responses and the excitability of nociceptive neuronal activity under in vivo conditions remain to be determined. The aim of the present study, therefore, was to investigate whether in vivo acute administration of ointment containing DA affects the excitability of nociceptive trigeminal spinal nucleus caudalis (SpVc) neurons associated with hypoalgesia in naïve rats. Results: After local application of DA, the threshold of escape from mechanical stimulation applied to the shaved orofacial skin was significantly higher than before DA application. Vehicle treatment (without DA) had no significant effect on the escape threshold from mechanical stimulation. Extracellular single unit recordings were made from SpVc wide-dynamic range (WDR) neurons in response to orofacial non-noxious and noxious mechanical stimuli of pentobarbital-anesthetized rats. The mean firing frequency of SpVc WDR neurons in response to noxious, but not non-noxious, mechanical stimuli was inhibited by local application of DA, and the maximum inhibition of discharge frequency of both non-noxious and noxious mechanical stimuli was seen within 1­5 min. The DA-induced short-term inhibitory effects were reversed after approximately 10 min. Pretreatment intravenously with the muscarinic-specific M2 receptor antagonist, methoctramine, abolished the DA-induced suppression of firing frequency of SpVc WDR neurons in response to noxious stimulation. Fluorogold (FG) labeling was identified as the trigeminal ganglion (TG) neurons innervating orofacial skin. FG-labeled small-diameter TG neurons expressed M2 receptor immunoreactivity. Conclusion: These results suggest that acute DA application induces short-term mechanical hypoalgesia and this effect was mainly due to suppression of the excitability of SpVc WDR neurons via the peripheral M2 receptor signaling pathway in the trigeminal primary afferents. These findings support the idea that DA is a potential therapeutic agent and complementary alternative medicine for the attenuation of trigeminal nociception in the absence of inflammatory/neuropathic conditions.


Subject(s)
Decanoic Acids/pharmacology , Nociceptors/drug effects , Receptor, Muscarinic M2/drug effects , Signal Transduction/drug effects , Action Potentials/drug effects , Animal Feed , Animals , Male , Rats, Wistar , Trigeminal Ganglion/drug effects , Trigeminal Nucleus, Spinal/cytology
10.
J Cardiovasc Pharmacol ; 69(6): 369-373, 2017 Jun.
Article in English | MEDLINE | ID: mdl-28328743

ABSTRACT

Atropine (ATr) is well known as a cholinergic antagonist, however, at low concentrations ATr could paradoxically accentuate the parasympathetic actions of acetylcholine (ACh). In 22 pentobarbital anesthetized dogs, via a left and right thoracotomy, a leak-proof barrier was attached to isolate the atrial appendages (AAs) from the rest of the atria. In group 1 (Ach+ATr+Ach), ACh, 100 mM, was placed on the AA followed by the application of ATr, 2 mg/mL. The average atrial fibrillation (AF) duration was 17 ± 7 minutes. After ATr was applied to the AA and ACh again tested, the AF duration was markedly attenuated (2 ± 2 minutes, P < 0.05). In group 2 (ATr+Ach), ATr was initially applied to the AA followed by the application of ACh, 100 mM. There was no significant difference in AF duration (16 ± 4 minutes vs. 18 ± 2 minutes, P = NS). The inhibitory effect of ATr on induced HR reduction (electrical stimulation of the anterior right ganglionated plexi and vagal nerves) was similar between groups 1 and 2. These observations suggest that when ATr is initially administered it attaches to the allosteric site of the muscarinic ACh receptor (M2) leaving the orthosteric site free to be occupied by ACh. The M3 receptor that controls HR slowing does not show the same allosteric properties.


Subject(s)
Acetylcholine/pharmacology , Anti-Arrhythmia Agents/pharmacology , Atrial Appendage/drug effects , Atrial Fibrillation/drug therapy , Atropine/pharmacology , Cholinergic Agonists/pharmacology , Heart Rate/drug effects , Muscarinic Antagonists/pharmacology , Acetylcholine/metabolism , Animals , Anti-Arrhythmia Agents/metabolism , Atrial Appendage/metabolism , Atrial Appendage/physiopathology , Atrial Fibrillation/etiology , Atrial Fibrillation/metabolism , Atrial Fibrillation/physiopathology , Atropine/metabolism , Binding Sites , Cardiac Pacing, Artificial , Cholinergic Agonists/metabolism , Disease Models, Animal , Dogs , Dose-Response Relationship, Drug , Drug Interactions , Muscarinic Antagonists/metabolism , Protein Binding , Receptor, Muscarinic M2/drug effects , Receptor, Muscarinic M2/metabolism , Time Factors
11.
BMC Gastroenterol ; 17(1): 21, 2017 Jan 26.
Article in English | MEDLINE | ID: mdl-28122499

ABSTRACT

BACKGROUND: Uridine (Urd), which has been reported as a major component of RNA, plays an important role in various biological process including neuroprotection, biochemical modulation and glycolysis, although its role in constipation has yet to be established. Therefore, in this study, we investigated the laxative effects of Urd on chronic constipation. METHODS: The constipation phenotypes and their related mechanisms were investigated in the transverse colons of SD rats with loperamide (Lop)-induced constipation after treatment with 100 mg/kg of Urd. RESULTS: The number, weight and water contents of stools were significantly higher in the Lop + Urd treated group than the Lop + Vehicle treated group, while food intake and water consumption of the same group were maintained at a constant level. The thickness of the mucosa layer, muscle and flat luminal surface, as well as the number of goblet cells, paneth cells and lipid droplets were enhanced in the Lop + Urd treated group. Furthermore, the expression of the muscarinic acetylcholine receptors M2 and M3 (mAChR M2 and M3) at the transcriptional and translational level was recovered in the Lop + Urd treated group, while some markers such as Gα and inositol triphosphate (IP3) in their downstream signaling pathway were completely recovered by Urd treatment. Moreover, the ability for mucin secretion and the expression of membrane water channel (aquaporine 8, AQP8) were increased significantly in the Lop + Urd treated group compared with Lop + Vehicle treated group. Finally, the activity of Urd was confirmed in primary smooth muscle of rat intestine cells (pRISMC) based on Gα expression and IP3 concentration. CONCLUSIONS: The results of the present study provide the first strong evidence that Urd can be considered an important candidate for improving chronic constipation induced by Lop treatment in animal models.


Subject(s)
Constipation/drug therapy , Constipation/metabolism , Laxatives/therapeutic use , Mucins/metabolism , Receptor, Muscarinic M2/metabolism , Receptor, Muscarinic M3/metabolism , Uridine/therapeutic use , Animals , Colon, Transverse/drug effects , Colon, Transverse/pathology , Colon, Transverse/ultrastructure , Disease Models, Animal , Feeding Behavior/drug effects , Inositol Phosphates/metabolism , Intestinal Mucosa/metabolism , Mucins/drug effects , Muscle, Smooth/metabolism , Rats, Sprague-Dawley , Receptor, Muscarinic M2/drug effects , Receptor, Muscarinic M3/drug effects , Signal Transduction , Uridine/metabolism , Uridine/pharmacology
12.
J Neurosci ; 35(50): 16418-30, 2015 Dec 16.
Article in English | MEDLINE | ID: mdl-26674867

ABSTRACT

Neuropathic pain is one of the most debilitating pain conditions, yet no therapeutic strategy has been really effective for its treatment. Hence, a better understanding of its pathophysiological mechanisms is necessary to identify new pharmacological targets. Here, we report important metabolic variations in brain areas involved in pain processing in a rat model of oxaliplatin-induced neuropathy using HRMAS (1)H-NMR spectroscopy. An increased concentration of choline has been evidenced in the posterior insular cortex (pIC) of neuropathic animal, which was significantly correlated with animals' pain thresholds. The screening of 34 genes mRNA involved in the pIC cholinergic system showed an increased expression of the high-affinity choline transporter and especially the muscarinic M2 receptors, which was confirmed by Western blot analysis in oxaliplatin-treated rats and the spared nerve injury model (SNI). Furthermore, pharmacological activation of M2 receptors in the pIC using oxotremorine completely reversed oxaliplatin-induced mechanical allodynia. Consistently, systemic treatment with donepezil, a centrally active acetylcholinesterase inhibitor, prevented and reversed oxaliplatin-induced cold and mechanical allodynia as well as social interaction impairment. Intracerebral microdialysis revealed a lower level of acetylcholine in the pIC of oxaliplatin-treated rats, which was significantly increased by donepezil. Finally, the analgesic effect of donepezil was markedly reduced by a microinjection of the M2 antagonist, methoctramine, within the pIC, in both oxaliplatin-treated rats and spared nerve injury rats. These findings highlight the crucial role of cortical cholinergic neurotransmission as a critical mechanism of neuropathic pain, and suggest that targeting insular M2 receptors using central cholinomimetics could be used for neuropathic pain treatment. SIGNIFICANCE STATEMENT: Our study describes a decrease in cholinergic neurotransmission in the posterior insular cortex in neuropathic pain condition and the involvement of M2 receptors. Targeting these cortical muscarinic M2 receptors using central cholinomimetics could be an effective therapy for neuropathic pain treatment.


Subject(s)
Analgesics/pharmacology , Cerebral Cortex/physiopathology , Cholinesterase Inhibitors/pharmacology , Indans/pharmacology , Neuralgia/physiopathology , Parasympathetic Nervous System/physiopathology , Piperidines/pharmacology , Receptor, Muscarinic M2/drug effects , Synaptic Transmission , Animals , Donepezil , Gene Expression/genetics , Hyperalgesia/chemically induced , Hyperalgesia/drug therapy , Interpersonal Relations , Male , Membrane Transport Proteins/metabolism , Muscarinic Antagonists/pharmacology , Neuralgia/chemically induced , Neuralgia/psychology , Organoplatinum Compounds , Oxaliplatin , RNA, Messenger/biosynthesis , RNA, Messenger/genetics , Rats , Rats, Sprague-Dawley , Receptor, Muscarinic M2/genetics
13.
Am J Psychiatry ; 172(11): 1131-40, 2015 Nov 01.
Article in English | MEDLINE | ID: mdl-26238605

ABSTRACT

OBJECTIVE: Gene expression dysregulation in the brain has been associated with bipolar disorder through candidate gene and microarray expression studies, but questions remain about isoform-specific dysregulation and the role of noncoding RNAs whose importance in the brain has been suggested recently but not yet characterized for bipolar disorder. METHOD: The authors used RNA sequencing, a powerful technique that captures the complexity of gene expression, in postmortem tissue from the anterior cingulate cortex from 13 bipolar disorder case subjects and 13 matched comparison subjects. Differential expression was computed, and a global pattern of downregulation was detected, with 10 transcripts significant at a false discovery rate ≤5%. Importantly, all 10 genes were also replicated in an independent RNA sequencing data set (N=61) from the anterior cingulate cortex. RESULTS: Among the most significant results were genes coding for class A G protein-coupled receptors: SSTR2 (somatostatin receptor 2), CHRM2 (cholinergic receptor, muscarinic 2), and RXFP1 (relaxin/insulin-like family peptide receptor 1). A gene ontology analysis of the entire set of differentially expressed genes pointed to an overrepresentation of genes involved in G protein-coupled receptor regulation. The top genes were followed up by querying the effect of treatment with mood stabilizers commonly prescribed in bipolar disorder, which showed that these drugs modulate expression of the candidate genes. CONCLUSIONS: By using RNA sequencing in the postmortem bipolar disorder brain, an interesting profile of G protein-coupled receptor dysregulation was identified, several new bipolar disorder genes were indicated, and the noncoding transcriptome in bipolar disorder was characterized. These findings have important implications with regard to fine-tuning our understanding of the bipolar disorder brain, as well as for identifying potential new drug target pathways.


Subject(s)
Bipolar Disorder/genetics , Gene Expression Regulation/genetics , Gyrus Cinguli/metabolism , RNA, Messenger/metabolism , Receptor, Muscarinic M2/genetics , Receptors, G-Protein-Coupled/genetics , Receptors, Peptide/genetics , Receptors, Somatostatin/genetics , Adult , Antimanic Agents/pharmacology , Bipolar Disorder/metabolism , Carbamazepine/pharmacology , Case-Control Studies , Cell Line , Female , Gene Expression Profiling , Gene Expression Regulation/drug effects , Humans , In Vitro Techniques , Lithium Compounds/pharmacology , Male , Middle Aged , Neural Stem Cells/drug effects , Neural Stem Cells/metabolism , RNA, Messenger/drug effects , Real-Time Polymerase Chain Reaction , Receptor, Muscarinic M2/drug effects , Receptors, G-Protein-Coupled/drug effects , Receptors, Peptide/drug effects , Receptors, Somatostatin/drug effects , Sequence Analysis, RNA , Valproic Acid/pharmacology
14.
Toxicol Appl Pharmacol ; 287(1): 9-16, 2015 Aug 15.
Article in English | MEDLINE | ID: mdl-26026369

ABSTRACT

Long acting inhaled muscarinic receptor antagonists, such as tiotropium, are widely used as bronchodilator therapy for chronic obstructive pulmonary disease (COPD). Although this class of compounds is generally considered to be safe and well tolerated in COPD patients the cardiovascular safety of tiotropium has recently been questioned. We describe a rat in vivo model that allows the concurrent assessment of muscarinic antagonist potency, bronchodilator efficacy and a potential for side effects, and we use this model to compare tiotropium with NVA237 (glycopyrronium bromide), a recently approved inhaled muscarinic antagonist for COPD. Anaesthetized Brown Norway rats were dosed intratracheally at 1 or 6h prior to receiving increasing doses of intravenous methacholine. Changes in airway resistance and cardiovascular function were recorded and therapeutic indices were calculated against the ED50 values for the inhibition of methacholine-induced bronchoconstriction. At both time points studied, greater therapeutic indices for hypotension and bradycardia were observed with glycopyrronium (19.5 and 28.5 fold at 1h; >200 fold at 6h) than with tiotropium (1.5 and 4.2 fold at 1h; 4.6 and 5.5 fold at 6h). Pharmacokinetic, protein plasma binding and rat muscarinic receptor binding properties for both compounds were determined and used to generate an integrated model of systemic M2 muscarinic receptor occupancy, which predicted significantly higher M2 receptor blockade at ED50 doses with tiotropium than with glycopyrronium. In our preclinical model there was an improved safety profile for glycopyrronium when compared with tiotropium.


Subject(s)
Bronchoconstriction/drug effects , Bronchodilator Agents/pharmacokinetics , Cardiovascular System/drug effects , Glycopyrrolate/pharmacokinetics , Muscarinic Antagonists/pharmacokinetics , Scopolamine Derivatives/pharmacokinetics , Airway Resistance/drug effects , Animals , Blood Pressure/drug effects , Bradycardia/chemically induced , Bradycardia/physiopathology , Bronchial Provocation Tests , Bronchodilator Agents/administration & dosage , Bronchodilator Agents/blood , Bronchodilator Agents/toxicity , Cardiovascular System/physiopathology , Glycopyrrolate/administration & dosage , Glycopyrrolate/blood , Glycopyrrolate/toxicity , Heart Rate/drug effects , Hypotension/chemically induced , Hypotension/physiopathology , Male , Models, Biological , Muscarinic Antagonists/administration & dosage , Muscarinic Antagonists/blood , Muscarinic Antagonists/toxicity , Protein Binding , Radioligand Assay , Rats, Inbred BN , Receptor, Muscarinic M2/drug effects , Receptor, Muscarinic M2/metabolism , Risk Assessment , Scopolamine Derivatives/administration & dosage , Scopolamine Derivatives/blood , Scopolamine Derivatives/toxicity , Tiotropium Bromide
15.
Urol J ; 11(3): 1642-7, 2014 Jul 08.
Article in English | MEDLINE | ID: mdl-25015611

ABSTRACT

PURPOSE: To locate the muscarinic (M) M2 and M3 receptors in bladder interstitial cells of Cajal (ICCs) and to determine the effects of M2 and M3 agonists on bladder ICCs. MATERIALS AND METHODS: A total of 30 adult male Sprague-Dawley rats weighing 225-250 g were used in this study. Double-labeled fluorescence of muscarinic receptors and c-kit was performed for co-localization. To evaluate the effect of muscarinic agents on the excitation of bladder ICCs, we analyzed the inward current of bladder ICCs using the whole-cell patch clamp. The effect of muscarinic agents on the carbachol-induced inward currents was evaluated with the whole-cell patch clamp. RESULTS: M2 and M3 receptors were confirmed in the stroma ICCs in rats' bladders with double-labeled immunofluorescence. Spontaneous action potential was observed in freshly isolated bladder ICCs. The carbachol-induced inward Ca2+ current in ICCs can be blocked by atropine. The M2 receptor antagonist methoctramine (1 µM) showed a weak inhibitory capability on the inward Ca2+ current [from 74.8 ± 9.6 to 63.3 ± 13.8 Pascal (pA), n = 12, P = .03]. While the M3 receptor antagonist 4-diphenyl-acetoxy-N-methyl-piperidine methiodide (4-DAMP) (1 µM) significantly inhibited the inward Ca2+ current (from 78.4 ± 11.2 to 17.3 ± 7.9 pA, n = 12, P < .001). CONCLUSION: Bladder ICCs express M2 and M3 cholinergic receptors. Most muscarinic cholinergic receptor antagonists, especially the M3 antagonists, can effectively inhibit the carbamylcholine- induced inward current of bladder ICCs.


Subject(s)
Calcium Channels/physiology , Interstitial Cells of Cajal/physiology , Receptor, Muscarinic M2/physiology , Receptor, Muscarinic M3/physiology , Action Potentials , Animals , Atropine/pharmacology , Calcium Channels/drug effects , Carbachol/pharmacology , Cholinergic Agonists/pharmacology , Diamines/pharmacology , Interstitial Cells of Cajal/chemistry , Male , Muscarinic Antagonists/pharmacology , Patch-Clamp Techniques , Piperidines/pharmacology , Rats , Rats, Sprague-Dawley , Receptor, Muscarinic M2/analysis , Receptor, Muscarinic M2/drug effects , Receptor, Muscarinic M3/analysis , Receptor, Muscarinic M3/drug effects , Urinary Bladder/chemistry , Urinary Bladder/physiology
16.
Am J Respir Cell Mol Biol ; 50(3): 493-501, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24074453

ABSTRACT

Brain natriuretic peptide (BNP) relaxes airways by activating natriuretic peptide receptor-A and elevating cyclic guanosine monophosphate. BNP is more effective in passively sensitized human bronchi compared with control airways. The molecular and cellular patterns involved in this signaling are unknown. The aim of this study was to investigate the influence of BNP on airway smooth muscle (ASM) cells obtained from donors with asthma and healthy donors and to identify the mechanisms involved in BNP-mediated relaxation. The contractile response of ASM cells was microscopically assessed in vitro in the presence of 1 µM BNP or with supernatant from human bronchial epithelial (BEAS-2B) cells pretreated with 1 µM BNP. We investigated the role of muscarinic M2 receptors and inducible nitric oxide synthase (iNOS), quantified the release of acetylcholine and nitric oxide (NO), and assessed the gene/protein expression of iNOS and myosin phosphatase target subunit 1 (MYPT1). Supernatant from BEAS-2B cells treated with BNP reduced the hyperreactivity of asthmatic ASM cells by shifting the potency of histamine by 1.19-fold but had no effect in healthy ASM cells. BNP was not effective directly on ASM cells. Blocking muscarinic M2-receptors and iNOS abolished the protective role of supernatant from BEAS-2B treated with BNP. BNP stimulated the release of acetylcholine (210.7 ± 11.1%) from BEAS-2B cells that in turn increased MYPT1 and iNOS gene/protein expression and enhanced NO levels in asthmatic ASM supernatant (35.0 ± 13.0%). This study provides evidence that BNP protects against bronchial hyperresponsiveness via an interaction between respiratory epithelium and ASM in subjects with asthma.


Subject(s)
Anti-Asthmatic Agents/pharmacology , Asthma/drug therapy , Bronchial Hyperreactivity/prevention & control , Bronchoconstriction/drug effects , Epithelial Cells/drug effects , Muscle, Smooth/drug effects , Myocytes, Smooth Muscle/drug effects , Natriuretic Peptide, Brain/pharmacology , Respiratory Mucosa/drug effects , Acetylcholine/metabolism , Asthma/genetics , Asthma/metabolism , Asthma/physiopathology , Bronchial Hyperreactivity/genetics , Bronchial Hyperreactivity/metabolism , Bronchial Hyperreactivity/physiopathology , Bronchoconstrictor Agents/pharmacology , Case-Control Studies , Cell Communication/drug effects , Cells, Cultured , Coculture Techniques , Culture Media, Conditioned/metabolism , Dose-Response Relationship, Drug , Epithelial Cells/metabolism , Humans , Muscle, Smooth/metabolism , Muscle, Smooth/physiopathology , Myocytes, Smooth Muscle/metabolism , Myosin-Light-Chain Phosphatase/genetics , Myosin-Light-Chain Phosphatase/metabolism , Nitric Oxide/metabolism , Nitric Oxide Synthase Type II/genetics , Nitric Oxide Synthase Type II/metabolism , Receptor, Muscarinic M2/drug effects , Receptor, Muscarinic M2/metabolism , Respiratory Mucosa/metabolism , Signal Transduction/drug effects
17.
Article in English | MEDLINE | ID: mdl-22660221

ABSTRACT

AIM: The present study was designed to investigate the effects of progesterone-carbachol derivative on perfusion pressure and coronary resistance in rats. An additional aim was to identify the molecular mechanisms involved. METHODS: The Langendorff model was used to measure perfusion pressure and coronary resistance changes in isolated rat heart after progesterone-carbachol derivative alone and after the following compounds; mifepristone (progesterone receptor blocker), yohimbine (α2 adreno-receptor antagonist), ICI 118,551 (selective ß2 receptor blocker), atropine (non-selective muscarinic receptor antagonist), methoctramine (antagonist of M2 receptor) and L-NAME (inhibitor of nitric oxide synthase). RESULTS: The results show that progesterone-carbachol derivative [10(-9) mM] significantly decreased perfusion pressure (P=0.005) and coronary resistance (P=0.006) in isolated rat heart. Additionally, the effect of progesterone-carbachol on perfusion pressure [10(-9) to 10(-4) mM] was only blocked in the presence of methoctramine and L-NAME. CONCLUSIONS: These data suggest that progesterone derivative exert its effect on perfusion pressure via activation of the M2 muscarinic. In addition, this phenomenon involves stimulation of nitric oxide synthase (NOS).


Subject(s)
Blood Pressure/drug effects , Carbachol/analogs & derivatives , Coronary Vessels/drug effects , Progesterone/analogs & derivatives , Receptor, Muscarinic M2/drug effects , Vascular Resistance/drug effects , Animals , Carbachol/pharmacology , Coronary Vessels/physiology , Male , Progesterone/pharmacology , Rats
18.
World J Gastroenterol ; 20(48): 18271-83, 2014 Dec 28.
Article in English | MEDLINE | ID: mdl-25561794

ABSTRACT

AIM: To investigate the effect and mechanism of acupuncture at heterotopic acupoints on jejunal motility, particularly in pathological conditions. METHODS: Jejunal motility was assessed using a manometric balloon placed in the jejunum approximately 18-20 cm downstream from the pylorus and filled with approximately 0.1 mL warm water in anesthetized normal rats or rats with diarrhea or constipation. The heterotopic acupoints including LI11 (Quchi), ST37 (Shangjuxu), BL25 (Dachangshu), and the homotopic acupoint ST25 (Tianshu), and were stimulated for 60 s by rotating acupuncture needles right and left at a frequency of 2 Hz. To determine the type of afferent fibers mediating the regulation of jejunal motility by manual acupuncture, the ipsilateral sciatic A or C fibers of ST37 were inactivated by local application of the A-fiber selective demyelination agent cobra venom or the C fiber blocker capsaicin. Methoctramine, a selective M2 receptor antagonist, was injected intravenously to identify a specific role for M2 receptors in mediating the effect of acupuncture on jejunal motility. RESULTS: Acupuncture at heterotopic acupoints, such as LI11 and ST37, increased jejunal motility not only in normal rats, but also in rats with constipation or diarrhea. In normal rats, manual acupuncture at LI11 or ST37 enhanced jejunal pressure from 7.34 ± 0.19 cmH2O to 7.93 ± 0.20 cmH2O, an increase of 9.05% ± 0.82% (P < 0.05), and from 6.95 ± 0.14 cmH2O to 8.97 ± 0.22 cmH2O, a significant increase of 27.44% ± 1.96% (P < 0.01), respectively. In constipated rats, manual acupuncture at LI11 or ST37 increased intrajejunal pressure from 8.17 ± 0.31 cmH2O to 9.86 ± 0.36 cmH2O, an increase of 20.69% ± 2.10% (P < 0.05), and from 8.82 ± 0.28 cmH2O to 10.83 ± 0.28 cmH2O, an increase of 22.81% ± 1.46% (P < 0.05), respectively. In rats with diarrhea, MA at LI11 or ST37 increased intrajejunal pressure from 11.95 ± 0.35 cmH2O to 13.96 ± 0.39 cmH2O, an increase of 16.82% ± 2.35% (P < 0.05), and tended to increase intrajejunal pressure (from 12.42 ± 0.38 cmH2O to 13.05 ± 0.38 cmH2O, an increase of 5.07% ± 1.08%, P > 0.05), respectively. In contrast, acupuncture ST25, a homotopic acupoint, decreased not only intrajejunal pressure, but also significantly decreased frequency in normal rats and rats with constipation or diarrhea. Following demyelination of Aδ fibers, acupuncture at ST37 again augmented intrajejunal pressure to 121.48% ± 3.06% of baseline. Following capsaicin application for 24 h, acupuncture at ipsilateral ST37 increased intrajejunal pressure significantly to 106.63% ± 1.26% of basal levels when compared to measurements prior to capsaicin treatment (P < 0.05). Acupuncture at LI11, ST37, or BL25 significantly rescued methoctramine-mediated inhibition of jejunal motility amplitude from 42.83% ± 1.65% to 53.43% ± 1.95% of baseline (P < 0.05), from 45.15% ± 2.22% to 70.51% ± 2.34% of baseline (P < 0.01), and from 38.03% ± 2.34% to 70.12% ± 2.22% of baseline (P < 0.01), respectively. CONCLUSION: Acupuncture at heterotopic acupoints increases the amplitude of jejunal motility in rats. C fibers and M2 receptors predominantly and partially mediate the regulation of jejunal motility by acupuncture, respectively.


Subject(s)
Acupuncture Points , Acupuncture Therapy/methods , Constipation/therapy , Diarrhea/therapy , Gastrointestinal Motility , Jejunum/physiopathology , Animals , Capsaicin/pharmacology , Constipation/metabolism , Constipation/physiopathology , Diamines/pharmacology , Diarrhea/metabolism , Diarrhea/physiopathology , Disease Models, Animal , Elapid Venoms/pharmacology , Jejunum/innervation , Male , Muscarinic Antagonists/pharmacology , Nerve Fibers, Myelinated/drug effects , Nerve Fibers, Unmyelinated/drug effects , Pressure , Rats, Sprague-Dawley , Receptor, Muscarinic M2/drug effects , Receptor, Muscarinic M2/metabolism , Sensory System Agents/pharmacology , Time Factors
19.
Eur Urol ; 64(3): 502-10, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23711542

ABSTRACT

BACKGROUND: First-line pharmacotherapy for overactive bladder consists of anticholinergics. However, patient compliance is exceptionally low, which may be due to progressive loss of effectiveness. OBJECTIVE: To decipher the involved molecular mechanisms and to evaluate the effects of chronic systemic administration of anticholinergics on bladder function and on muscarinic and purinergic receptors expression in rats. DESIGN, SETTING, AND PARTICIPANTS: Female Wistar rats were implanted with an osmotic pump that chronically administered vehicle (Vehc), 0.36 mg/kg per day oxybutynin (Oxyc), or 0.19 mg/kg per day fesoterodine (Fesoc) for 28 d. INTERVENTIONS: For cystometry experiments, a small catheter was implanted in the bladder. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Urologic phenotype was evaluated by the analysis of the micturition pattern and urodynamics. Expression of muscarinic and purinergic receptors was assessed by Western blot analysis of detrusor membrane protein. Functional responses to carbachol and adenosine triphosphate (ATP) were evaluated using muscle-strip contractility experiments. RESULTS AND LIMITATIONS: The number of voided spots was transiently decreased in Oxyc rats. In Oxyc rats, the effect of an acute high dose of oxybutynin (1mg/kg intraperitoneally [IP]) on the intermicturition interval was abolished. Expression experiments revealed a decrease of muscarinic acetylcholine receptors M2 (mAChR2) and M3 (mAChR3), whereas the purinergic receptor P2X, ligand-gated ion channel, 1 (P2X1) was enhanced in Oxyc and Fesoc rats compared to Vehc rats. In concordance with the modification of the expression pattern in Oxyc rats, the force generated by carbachol and ATP in muscle-strip contractility experiments was, respectively, lower and higher. Urodynamics revealed that the effects of systemic administration of the purinergic blocker pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (50mg/kg IP) were enhanced in Oxyc rats. As rat bladder physiology is different from that of humans, it is difficult to directly extrapolate our findings to human patients. CONCLUSIONS: Chronic administration of anticholinergics in rats induces receptor loss of efficiency and a shift from muscarinic to purinergic transmission.


Subject(s)
Benzhydryl Compounds/administration & dosage , Cholinergic Antagonists/administration & dosage , Cholinergic Neurons/drug effects , Mandelic Acids/administration & dosage , Purines/metabolism , Receptors, Muscarinic/drug effects , Receptors, Purinergic P2X1/drug effects , Synaptic Transmission/drug effects , Urinary Bladder/innervation , Urological Agents/administration & dosage , Animals , Cholinergic Agonists/pharmacology , Cholinergic Neurons/metabolism , Female , Infusion Pumps, Implantable , Muscle Contraction/drug effects , Purinergic P2X Receptor Agonists/pharmacology , Purinergic P2X Receptor Antagonists/pharmacology , Rats , Rats, Wistar , Receptor, Muscarinic M2/drug effects , Receptor, Muscarinic M2/metabolism , Receptor, Muscarinic M3/drug effects , Receptor, Muscarinic M3/metabolism , Receptors, Muscarinic/metabolism , Receptors, Purinergic P2X1/metabolism , Time Factors , Urinary Catheterization , Urination/drug effects , Urodynamics/drug effects
20.
Urology ; 81(5): 1052-7, 2013 May.
Article in English | MEDLINE | ID: mdl-23419459

ABSTRACT

OBJECTIVE: To analyze the effect of OnabotulinumtoxinA detrusor injections on postsynaptic muscular receptors in children and adolescents with neurogenic detrusor overactivity. MATERIALS AND METHODS: A bladder augmentation became necessary in 10 children and adolescents (7 males, 3 females; median age, 12 years) who had neurogenic detrusor overactivity. Seven had previously received 1 to 8 (average 3.86) OnabotulinumtoxinA detrusor injections, but their detrusor pressure could not be maintained at tolerable levels because of low-compliance bladder. The last injection session had been completed an average of 3 months (range, 1.5-3.5 months) previously. Three patients had never received that therapy and were considered controls. On the bladder dome resections, a specific receptor analysis (muscarinic M2 and M3 and purinergic P2X1, P2X2, and P2X3) was performed with confocal immunofluorescence, and nerve fiber density was analyzed with light-microscopic 3,3'-diaminobenzidine-immunohistochemical staining. RESULTS: Receptor analysis showed a downregulation of all examined receptors after OnabotulinumtoxinA injections; the reductions in M2, M3, P2X2, and P2X3 receptors reached a significance level of P <.05 (Mann-Whitney test). The ratios of means (OnabotulinumtoxinA-to-control) were 0.26 for M2, 0.33 for M3, 0.35 for P2X1, 0.19 for P2X2, and 0.37 for P2X3. CONCLUSION: OnabotulinumtoxinA detrusor injections led to significant reductions in muscular M2, M3, P2X2, and P2X3 receptors. The reductions probably affect the generated force in the urinary bladder and could contribute to the clinically observed increase in residual urine.


Subject(s)
Botulinum Toxins, Type A/administration & dosage , Down-Regulation , Receptor, Muscarinic M2/biosynthesis , Receptor, Muscarinic M3/biosynthesis , Receptors, Purinergic P2X2/biosynthesis , Receptors, Purinergic P2X3/biosynthesis , Urinary Bladder, Overactive/drug therapy , Adolescent , Adult , Child , Dose-Response Relationship, Drug , Female , Follow-Up Studies , Humans , Immunohistochemistry , Injections , Male , Neuromuscular Agents/administration & dosage , Prospective Studies , Receptor, Muscarinic M2/drug effects , Receptor, Muscarinic M3/drug effects , Receptors, Purinergic P2X2/drug effects , Receptors, Purinergic P2X3/drug effects , Single-Blind Method , Treatment Outcome , Urinary Bladder, Overactive/metabolism , Urinary Bladder, Overactive/physiopathology , Urodynamics/drug effects , Young Adult
SELECTION OF CITATIONS
SEARCH DETAIL
...