Effect of moxibustion on M2 and P2X3 receptors of bladder tissue in rats with neurogenic bladder of detrusor areflexia after lumbar-sacral spinal cord injury / 中国针灸

OBJECTIVE@#To observe the effect of moxibustion at "Guanyuan" (CV 4) and "Shenque" (CV 8) on acetylcholine (Ach), adenosine triphosphate (ATP) and muscarinic-type choline receptor (M2) and purine receptor P2X3 in bladder tissue in the rats with neurogenic bladder (NB) of detrusor areflexia after lumbar-sacral spinal cord injury and explore the underlying mechanism of moxibustion for promoting detrusor contraction.@*METHODS@#Sixty SD rats were randomly divided into a model preparation group (n=45) and a sham-operation group (n=15). In the model preparation group, the modified Hassan Shaker spinal cord transection method was used to prepare the model of NB. In the sham-operation group, the spinal cord transection was not exerted except laminectomy and spinal cord exposure. Among the rats with successfully modeled, 30 rats were selected and divided randomly into a model group and a moxibustion group, with 15 rats in each one. On the 15th day after the operation, moxibustion was applied at "Guanyuan" (CV 4) and "Shenque" (CV 8) in the moxibustion group, 10 min at each acupoint, once a day. The consecutive 7-day treatment was as one course and the intervention for 2 courses was required. Urodynamic test was adopted to evaluate bladder function in rats. Using HE staining, the morphological changes in bladder tissue were observed. The content of Ach and ATP in bladder tissue was measured with biochemical method, and the protein and mRNA expression levels of M2 and P2X3 receptors in bladder tissue were detected with Western blot and real-time fluorescence quantification PCR method.@*RESULTS@#Compared with the sham-operation group, the maximum bladder capacity, leakage point pressure and bladder compliance were increased in the rats of the model group (P<0.05). Compared with the model group, the maximum bladder capacity, the leakage point pressure and bladder compliance were decreased in the rats of the moxibustion group (P<0.05). In the model group, the detrusor fibres were arranged irregularly, bladder epithelial tissues were not tightly connected and cell arrangement was disordered, combined with a large number of vacuolar cells. In the moxibustion group, compared with the model group, the detrusor fibres were arranged regularly, bladder epithelial cells were well distributed and vacuolar cells were reduced. Compared with the sham-operation group, the content of Ach and ATP in bladder tissue was decreased (P<0.05), the protein and mRNA expression levels of M2 and P2X3 receptors were reduced (P<0.05) in the model group. In the moxibustion group, the content of Ach and ATP in bladder tissue was increased (P<0.05) and the protein and mRNA expression levels of M2 and P2X3 receptors were increased (P<0.05) as compared with the model group.@*CONCLUSION@#Moxibustion at "Guanyuan" (CV 4) and "Shenque" (CV 8) may effectively improve bladder function in the rats with NB of detrusor areflexia after lumbar-sacral spinal cord injury and its underlying mechanism is related to promoting the release of Ach and up-regulating the expression of M2 receptor, thereby enhancing the release of ATP and increasing the expression of P2X3 receptor. Eventually, detrusor contraction is improved.

Cough Hypersensitivity Syndrome: A Few More Steps Forward

Cough reflex is a vital protective mechanism against aspiration, but when dysregulated, it can become hypersensitive. In fact, chronic cough is a significant medical problem with a high degree of morbidity. Recently, a unifying paradigm of cough hypersensitivity syndrome has been proposed. It represents a clinical entity in which chronic cough is a major presenting problem, regardless of the underlying condition. Although it remains a theoretical construct, emerging evidence suggests that aberrant neurophysiology is the common etiology of this syndrome. Recent success in randomized clinical trials using a P2X3 receptor antagonist is the first major advance in the therapeutics of cough in the past 30 years; it at last provides a strategy for treating intractable cough as well as an invaluable tool for dissecting the mechanism underpinning cough hypersensitivity. Additionally, several cough measurement tools have been validated for use and will help assess the clinical relevance of cough in various underlying conditions. Along with this paradigm shift, our understanding of cough mechanisms has improved during the past decades, allowing us to continue to take more steps forward in the future.

Current Pharmacologic Approaches in Painful Bladder Research: An Update / 대한배뇨장애요실금학회지

The symptoms of interstitial cystitis (IC)/bladder pain syndrome (BPS) may have multiple causes and involve many contributing factors. Traditional treatments (intravesical instillations) have had a primary focus on the bladder as origin of symptoms without adequately considering the potential influence of other local (pelvic) or systemic factors. Systemic pharmacological treatments have had modest success. A contributing factor to the low efficacy is the lack of phenotyping the patients. Individualized treatment based on is desirable, but further phenotype categorization is needed. There seems to be general agreement that IC is a unique disease and that BPS is a syndrome with multiple pathophysiologies, but this has so far not been not been well reflected in preclinical research with the aim of finding new pharmacological treatments. Current research approaches, including anti-nerve growth factor treatment, anti-tumor necrosis factor-α treatment, activation of SHIP1 (AQX-1125), and P2X3 receptor antagonists, and α1-adrenoceptor antagonists are potential systemic treatments, implying that not only the bladder is exposed to the administered drug, which may be beneficial if the IC/BPS is a bladder manifestation of a systemic disease, or negative (adverse effects) if it is a local bladder condition. Local treatment approaches such as the antagonism of Toll-like receptors (which still is only experimental) and intravesical liposomes (with positive proof-of-concept), may have the advantages of a low number of systemic adverse effects, but cannot be expected to have effects on symptoms generated outside the bladder. Assessment of which of the treatment approaches discussed in this review that can be developed into useful therapies requires further studies.

Effect of Zhuangyao Jianshen Wan (ZYJCW) on P2X1 and P2X3 mRNA expressions in rats with diuresis caused by kidney deficiency / 中国中药杂志

To investigate the urination-reducing effect and mechanism of Zhuangyao Jianshen Wan (ZYJCW). In this study, SI rats were subcutaneously injected with 150 mg · kg(-1) dose of D-galactose to prepare the sub-acute aging model and randomly divided into the model group, the Suoquan Wan group (1.17 g · kg(-1) · d(-1)), and ZYJCW high, medium and low dose groups (2.39, 1.20, 0.60 g · kg(-1) · d(-1)) , with normal rats in the blank group. They were continuously administered with drugs for eight weeks. The metabolic cage method was adopted to measure the 24 h urine volume and 5 h water load urine volume in rats. The automatic biochemistry analyzer was adopted to detect urine concentrations of Na+, Cl-, K+. The ELISA method was used to determine serum aldosterone (ALD) and antidiuretic hormone (ADH). The changes in P2X1 and P2X3 mRNA expressions in bladder tissues of rats were detected by RT-PCR. According to the results, both ZYJCW high and medium dose groups showed significant down-regulations in 24 h urine volume and 5 h water load urine volume in (P <0.05, P <0.01), declines in Na+ and Cl- concentrations in urine (P <0.01), notable rises in plasma ALD and ADH contents (P <0.05, P <0.01) and remarkable down-regulations in the P2X1 and P2X3 mRNA expressions in bladder tissues (P <0.01). The ZYJCW low dose group revealed obvious reductions in Na+ and Cl- concentrations in urine (P <0.01). The results indicated that ZYJCW may show the urination-reducing effect by down-regulating the P2X1 and P2X3 mRNA expressions in bladder tissues of rats with diuresis caused by kidney deficiency.

Upregulation of P2X3 receptors in dorsal root ganglion of TRPV1 knockout female mice / 生理学报

The study was aimed to investigate the changes in mechanical pain threshold in the condition of chronic inflammatory pain after transient receptor potential vanilloid 1 (TRPV1) gene was knockout. Hind-paw intraplantar injection of complete freund's adjuvant (CFA, 20 μL) produced peripheral inflammation in wild-type and TRPV1 knockout female mice. The mechanical pain thresholds were measured during the 8 days after injection and pre-injection by using Von-Frey hair. Nine days after injection, mice were killed and the differences of expression of c-Fos and P2X3 receptor in the dorsal root ganglia (DRG) and spinal cord dorsal horn were examined by Western blotting between the two groups. Compared with that in wild-type mice, the mechanical pain threshold was increased significantly in TRPV1 knockout mice (P < 0.05); 3 days after CFA injection, the baseline mechanical pain threshold in the TRPV1 knockout mice group was significantly higher than that in the wild-type mice group (P < 0.05); The result of Western blotting showed that the expression of c-Fos protein both in DRG and spinal cord dorsal horn of TRPV1 knockout mice group was decreased significantly compared with that in wild-type mice group (P < 0.01, P < 0.05), while the expression of P2X3 receptor in DRG of TRPV1 knockout mice group was increased significantly compared with that in wild-type mice group (P < 0.05). Our findings indicate that TRPV1 may influence the peripheral mechanical pain threshold by mediating the expression of c-Fos protein both in DRG and spinal cord dorsal horn and changing the expression of P2X3 receptor in DRG.

Effect of electroacupuncture on the pathomorphology of the sciatic nerve and the sensitization of P2X₃ receptors in the dorsal root ganglion in rats with chronic constrictive injury / 中国结合医学杂志

<p><b>OBJECTIVE</b>To explore the effect of electroacupuncture (EA) on the pathomorphology of the sciatic nerve and the role of P2X3 receptors in EA analgesia.</p><p><b>METHODS</b>The chronic constriction injury (CCI) model was adopted in this study. A total of 32 rats were randomly divided into four groups: sham CCI, CCI, CCI plus contralateral EA (CCI + conEA) and CCI plus ipsilateral EA (CCI + ipsEA). Mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) were measured. EA began at day 7 after the CCI operation and was applied to the Zusanli (ST 36) and Yanglingquan acupoints (GB 34). At day 14, the pathomorphologic changes of the operated sciatic nerve were demonstrated by hematoxylin and eosin staining. In addition, dorsal root ganglion (DRG) neurons isolated from rats were examined by electrophysiological recording to determine if the P2X3 receptor agonists, adenosine 5'-triphosphate disodium (ATP) and α,β-methylen-ATP (α,β-meATP) evoked inward currents.</p><p><b>RESULTS</b>Pain thresholds in the CCI group were obviously decreased post CCI surgery (P<0.01). In the EA groups, thermal and mechanical threshold values were increased after the last EA treatment (P<0.05, P<0.01). There was no significant difference in light microscopic examination among the four groups (P>0.05). Current amplitude after application of ATP and α,β-meATP in DRG neurons were much larger in the CCI group compared to those obtained in sham CCI (P<0.05). ATP and α, β-meATP invoked amplitudes in the CCI + EA groups were reduced. There was no signififi cant difference between the CCI + conEA group and the CCI + ipsEA group (P>0.05).</p><p><b>CONCLUSION</b>EA analgesia may be mediated by decreasing the response of P2X3 receptors to the agonists ATP and α,β-meATP in the DRG of rats with CCI. No pathological changes of the sciatic nerve of rats were observed after EA treatment.</p>

P2X3, but not P2X1, receptors mediate ATP-activated current in neurons innervating tooth-pulp / 华中科技大学学报（医学）（英德文版）

We developed a method that allows us to label nociceptive neurons innervating tooth-pulp in rat trigeminal ganglion neurons using a retrograde fluorescence-tracing method, to record ATP-activated current in freshly isolated fluorescence-labeled neurons and to conduct single cell immunohistochemical staining for P2X1 and P2X3 subunits in the same neuron. Three types of ATP-activated current in these neurons (F, I and S) were recorded. The cells exhibiting the type F current mainly showed positive staining for P2X3, but negative staining for P2X1. The results provide direct and convincing evidence at the level of single native nociceptive neurons for correlation of the characteristics of ATP-activated currents with their composition of P2X1 and P2X3 subunits and cell size. The results also suggest that the P2X3, but not P2X1, is the main subunit that mediates the fast ATP-activated current in nociceptive neurons.

Expression of ligand-gated cation channels P2X3 receptor in rat pulp during experimental tooth movement / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate ligand-gated cation channels P2X3 receptors changes in rat pulp during experimental tooth movement (ETM), and preliminarily find their possible effect during ETM.</p><p><b>METHODS</b>54 male SD rats (200-250 g) were selected and randomly divided into blank group (5 rats), control group (14 rats) and experimental group (35 rats). The left maxillary first molar was selected as observation object, the pulp tissue biopsies was taken at different time points to carry out immunohistochemical study.</p><p><b>RESULTS</b>Predominant up regulation of P2X3 receptors immunoactivity was found in pulp from 1/6 d to 7 d after experimental tooth movement. It started to significantly increase at 1/6 d, peaked at 3 d, and then decreased continuously until 7 d as compared with the beginning.</p><p><b>CONCLUSION</b>P2X3 receptors have a rhythm change in rat pulp as a result of ETM, speculated that P2X3 receptors is closely related to the tooth movement injury, but the mechanism of action need further researches.</p>

Bradykinin modulates ion channel in inflammatory pain / 药学学报

Injury or inflammation induces release of a range of inflammatory mediators. Bradykinin is one of the most important inflammatory mediators and plays a crucial role in mediating inflammatory pain. It is well known that multiple ion channels located in the nociceptors participate in pain sensation. Recent studies demonstrate an important role of bradykinin in regulating the function and expression of pain-related ion channels. This paper summarizes the recent advances in the understanding of the role of bradykinin in modulation of the channels and discusses future possibilities in the treatment of inflammatory pain.

Expression of P2X3 and its colocalization with trpv1 in the human dental pulp / 대한치과보존학회지

The purinoreceptor, P2X3 is a ligand-gated cation channel activated by extracellular ATP. It has been reported that ATP can be released during inflammation and tissue damage, which in turn may activate P2X3 receptors to initiate nociceptive signals. However, little is known about the contribution of P2X3 to the dental pain during pulpal inflammation. Therefore, the purpose of this study was to investigate the expression of P2X3 and its colocalization with TRPV1 to understand the mechanism of pain transmission through P2X3 in the human dental pulp with double labeling immunofluorescence method. In the human dental pulp, intense P2X3 immunoreactivity was observed throughout the coronal and radicular pulp. Of all P2X3-positive fibers examined, 79.4% coexpressed TRPV1. This result suggests that P2X3 along with TRPV1 may be involved in the transmission of pain and potentiation of noxious stimuli during pulpal inflammation.

Differential regulation of P2X3 protein expression in the rat trigeminal ganglion after experimental tooth movement / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the regulation of P2X3 protein expression in the trigeminal ganglion sensory neurons after the nociceptive stimulation by orthodontic tooth movement force.</p><p><b>METHODS</b>Male Sprague-Dawley rats weighing 200-250 g were used. The mimic tooth movement appliance was used in experimental group rats. The animals were sacrificed after 4 h, 1 d, 2 d, 3 d, 5 d, 7 d and 14 d. The semi-quality of P2X3 protein was measured by Western blot. The expression place and strength of P2X3 was detected by in situ hybridization with an oligonucleotide probe in the same time.</p><p><b>RESULTS</b>A major specific protein of 4.5 x 10(4) was found by Western blot in trigeminal ganglion of rats. The expression strength of P2X3 receptor increased after given force to the teeth of rats from 1 day of experiment, 3 day group rats showed peak change. 14 day group had returned to control values. The level change of P2X3 mRNA expression showed the same result.</p><p><b>CONCLUSION</b>The results suggest that the P2X3 receptor expression is transiently upregulated and anterogradely transported in trigeminal primary sensory neurons after orthodontic tooth movement and that P2X3 receptor may play role in the pathomechanism of nociceptive in primary sensory neurons during orthodontic clinic treatment.</p>