The Inhibitory Mechanism on Acetylcholine-Induced Contraction of Bladder Smooth Muscle in the Streptozotocin-Induced Diabetic Rat

Most diabetic patients experience diabetic mellitus (DM) urinary bladder dysfunction. A number of studies evaluate bladder smooth muscle contraction in DM. In this study, we evaluated the change of bladder smooth muscle contraction between normal rats and DM rats. Furthermore, we used pharmacological inhibitors to determine the differences in the signaling pathways between normal and DM rats. Rats in the DM group received an intraperitoneal injection of 65 mg/kg streptozotocin and measured blood glucose level after 14 days to confirm DM. Bladder smooth muscle contraction was induced using acetylcholine (ACh, 10⁻⁴ M). The materials such as, atropine (a muscarinic receptor antagonist), U73122 (a phospholipase C inhibitor), DPCPX (an adenosine A1 receptor antagonist), udenafil (a PDE5 inhibitor), prazosin (an α₁-receptor antagonist), papaverine (a smooth muscle relaxant), verapamil (a calcium channel blocker), and chelerythrine (a protein kinase C inhibitor) were pre-treated in bladder smooth muscle. We found that the DM rats had lower bladder smooth muscle contractility than normal rats. When prazosin, udenafil, verapamil, and U73122 were pre-treated, there were significant differences between normal and DM rats. Taken together, it was concluded that the change of intracellular Ca²⁺ release mediated by PLC/IP3 and PDE5 activity were responsible for decreased bladder smooth muscle contractility in DM rats.

Sleep Promoting Effect of Luteolin in Mice via Adenosine A1 and A2A Receptors

Luteolin, a widespread flavonoid, has been known to have neuroprotective activity against various neurologic diseases such as epilepsy, and Alzheimer’s disease. However, little information is available regarding the hypnotic effect of luteolin. In this study, we evaluated the hypnotic effect of luteolin and its underlying mechanism. In pentobarbital-induced sleeping mice model, luteolin (1, and 3 mg/kg, p.o.) decreased sleep latency and increased the total sleep time. Through electroencephalogram (EEG) and electromyogram (EMG) recording, we demonstrated that luteolin increased non-rapid eye movement (NREM) sleep time and decreased wake time. To evaluate the underlying mechanism, we examined the effects of various pharmacological antagonists on the hypnotic effect of luteolin. The hypnotic effect of 3 mg/kg of luteolin was not affected by flumazenil, a GABAA receptor-benzodiazepine (GABAAR-BDZ) binding site antagonist, and bicuculine, a GABAAR-GABA binding site antagonist. On the other hand, the hypnotic effect of 3 mg/kg of luteolin was almost completely blocked by caffeine, an antagonist for both adenosine A1 and A2A receptor (A1R and A2AR), 8-Cyclopentyl-1,3-dipropylxanthine (DPCPX), an A1R antagonist, and SCH-58261, an A2AR antagonist. From the binding affinity assay, we have found that luteolin significantly binds to not only A1R but also A2AR with IC₅₀ of 1.19, 0.84 μg/kg, respectively. However, luteolin did not bind to either BDZ-receptor or GABAAR. From these results, it has been suggested that luteolin has hypnotic efficacy through A1R and A2AR binding.

Involvement of adenosine A1 receptor in electroacupuncture-mediated inhibition of astrocyte activation during neuropathic pain / Envolvimento do receptor de adenosina A1 na inibição da ativação de astrócitos mediada por eletroacupuntura durante a dor neuropática

ABSTRACT Neuropathic pain is a chronic pain condition caused by damage or dysfunction of the central or peripheral nervous system. Electroacupuncture (EA) has an antinociceptive effect on neuropathic pain, which is partially due to inhibiting astrocyte activation in the spinal cord. We found that an intrathecal injection of 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), a selective adenosine A1 receptor antagonist, reversed the antinociceptive effects of EA in a chronic constriction injury-induced neuropathic pain model. The expression of GFAP in L4-L6 spinal cord was significantly upgraded, while DPCPX suppressed the effect of the EA-mediating inhibition of astrocyte activation, as well as wiping out the EA-induced suppression of cytokine content (TNF-α). These results indicated that the adenosine A1 receptor is involved in EA actions during neuropathic pain through suppressing astrocyte activation as well as TNF-α upregulation of EA, giving enlightenment to the mechanisms of acupuncture analgesia and development of therapeutic targets for neuropathic pain.

RESUMO A dor neuropática é uma condição de dor crônica causada por dano ou disfunção do sistema nervoso central ou periférico. A eletroacupuntura (EA) tem um efeito antinociceptivo durante a dor neuropática, que é parcialmente devido à inibição da ativação de astrócitos na medula espinhal. Descobrimos que a injeção intratecal de 8-ciclopentil-1,3-dipropilxantina (DPCPX), um antagonista seletivo do receptor de adenosina A1, reverteu os efeitos antinociceptivos da EA no modelo de dor neuropática induzida por lesão por constrição crônica (CCI). A expressão da GFAP na medula espinal L4-L6 foi significativamente melhorada, enquanto a DPCPX suprimiu o efeito da inibição mediadora da EA na ativação de astrócitos, bem como eliminou a supressão induzida pela EA do conteúdo de citocina (TNF-α). Esses resultados indicam que o receptor de adenosina A1 está envolvido nas ações da EA durante a dor neuropática, suprimindo a ativação astrocitária, bem como o aumento da TNF-α na EA, fornecendo esclarecimentos sobre os mecanismos de analgesia da acupuntura e o desenvolvimento de alvos terapêuticos para dor neuropática.

Effects of adenosine receptor agonist on the rocuronium-induced neuromuscular block and sugammadex-induced recovery / 대한마취과학회지

BACKGROUND: Several types of receptors are found at neuromuscular presynaptic membranes. Presynaptic inhibitory A1 and facilitatory A2A receptors mediate different modulatory functions on acetylcholine release. This study investigated whether adenosine A1 receptor agonist contributes to the first twitch tension (T1) of train-of-four (TOF) stimulation depression and TOF fade during rocuronium-induced neuromuscular blockade, and sugammadex-induced recovery. METHODS: Phrenic nerve-diaphragm tissues were obtained from 30 adult Sprague-Dawley rats. Each tissue specimen was randomly allocated to either control group or 2-chloroadenosine (CADO, 10 μM) group. One hour of reaction time was allowed before initiating main experimental data collection. Loading and boost doses of rocuronium were sequentially administered until > 95% depression of the T1 was achieved. After confirming that there was no T1 twitch tension response, 15 min of resting time was allowed, after which sugammadex was administered. Recovery profiles (T1, TOF ratio [TOFR], and recovery index) were collected for 1 h and compared between groups. RESULTS: There were statistically significant differences on amount of rocuronium (actually used during experiment), TOFR changes during concentration-response of rocuronium (P = 0.04), and recovery profiles (P < 0.01) of CADO group comparing with the control group. However, at the initial phase of this experiment, dose-response of rocuronium in each group demonstrated no statistically significant differences (P = 0.12). CONCLUSIONS: The adenosine A1 receptor agonist (CADO) influenced the TOFR and the recovery profile. After activating adenosine receptor, sugammadex-induced recovery from rocuronium-induced neuromuscular block was delayed.

Caffeine teratogenicity in rats: morphological characterization and hypothesized mechanisms

Caffeine consumption during pregnancy has been shown in the scientific literature to be associated with teratogenicity such as low birth weight, fetal malformations, and miscarriage. However, the morphological alterations of the offspring of dams exposed during pregnancy have not been consistently described, and the mechanisms why they occur remain elusive. Thus, we aimed to characterize the offspring malformations induced by moderate and high doses of caffeine during pregnancy. Dams were divided into three groups: control, moderate (0.3 g/L), and high dose (1.0 g/L) of caffeine, which was provided in the drinking water beginning on gestational day 1 and continuing throughout the entire gestation. At moderate doses, only one of the dams had stillborn pups, although no macroscopic malformations were observed. High doses of caffeine induced significantly more malformations (P<0.001) and early death (before P4). The malformations observed were related to fetal development and cardiovascular alterations, namely bruises, macrocephaly with short limbs, abnormal development (or absence) of head structures and limbs, labial malformations, hydrops fetalis, and poor placental formation. We discussed the proposed mechanisms by which caffeine might induce these phenotypes, which may involve down-regulation of adenosine A1 receptors, and increased mothers' catecholamines. Our findings further confirm the evidence of the teratogenic effects of high doses of caffeine administered during pregnancy. These findings support the recommendation to avoid caffeine exposure during pregnancy (AU)

Adenosine Al Receptor Mediated Neuroprotection of Shenmai Injection on Rat Cerebral Ischemia/Reperfusion Injury: an Experimental Study / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To observe whether adenosine Al receptor (Al R) mediated neuroprotection of Shenmai Injection (SI) on rat cerebral ischemia/reperfusion (I/R) injury.</p><p><b>METHODS</b>The focal cerebral I/R model was established by middle cerebral artery occlusion (MCAO). Totally 60 successfully modeled rats was divided into 5 groups according to randomized block principle, i.e., the model group, the SI group, the SI + AlR antagonist (1,3-dipropyl-8-cyclopentylxanthine, DPCPX) group, the AlR antagonist control group, and the dimethyl sulfoxide (DMSO) control group, 12 in each group. Besides, a sham-operation group was set up (n =12). SI at 15 mL/kg was peritoneally injected to mice in the SI group immediately after cerebral I/R. Equal volume of normal saline was injected to mice in the model group and the sham-operation group. DPCPX at 1 mg/mL was peritoneally injected to mice in the Al R antagonist control group 30 min before peritoneal injecting SI. DPCPX at 1 mg/kg and DMSO at 1 mL/kg were peritoneally injected to mice in the AlR antagonist control group and the DMSO control group 30 min immediately before cerebral I/R. Rats' neurobehavioral scores were assessed after 24 h reperfusion. The volume of cerebral infarction and Bcl-2 protein expression of cerebral infarction penumbra were also detected. Results Compared with the sham-operation group, neurobehavioral scores, the volume of cerebral infarction, and Bcl-2 protein expression increased (all P <0. 05). Compared with the model group, neurobehavioral scores and the volume of cerebral infarction obviously decreased, but Bcl-2 protein expression increased in the SI group (all P <0. 05). Compared with the SI group, neurobehavioral scores increased, the volume of cerebral infarction was obviously enlarged, and Bcl-2 protein expression was obviously reduced in the A1R antagonist control group (all P <0. 05).</p><p><b>CONCLUSIONS</b>SI's neurobehavioral scores could be partially reversed in the Al R antagonist control group, the volume of cerebral infarction and Bcl-2 protein expression improved. AlR might possibly meditate neuroprotection of SI on MACO mire</p>

Chronic caffeine exposure attenuates blast-induced memory deficit in mice / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the effects of three different ways of chronic caffeine administration on blast- induced memory dysfunction and to explore the underlying mechanisms.</p><p><b>METHODS</b>Adult male C57BL/6 mice were used and randomly divided into five groups: control: without blast exposure, con-water: administrated with water continuously before and after blast-induced traumatic brain injury (bTBI), con-caffeine: administrated with caffeine continuously for 1 month before and after bTBI, pre-caffeine: chronically administrated with caffeine for 1 month before bTBI and withdrawal after bTBI, post-caffeine: chronically administrated with caffeine after bTBI. After being subjected to moderate intensity of blast injury, mice were recorded for learning and memory performance using Morris water maze (MWM) paradigms at 1, 4, and 8 weeks post-blast injury. Neurological deficit scoring, glutamate concentration, proinflammatory cytokines production, and neuropathological changes at 24 h, 1, 4, and 8 weeks post-bTBI were examined to evaluate the brain injury in early and prolonged stages. Adenosine A1 receptor expression was detected using qPCR.</p><p><b>RESULTS</b>All of the three ways of chronic caffeine exposure ameliorated blast-induced memory deficit, which is correlated with the neuroprotective effects against excitotoxicity, inflammation, astrogliosis and neuronal loss at different stages of injury. Continuous caffeine treatment played positive roles in both early and prolonged stages of bTBI; pre-bTBI and post-bTBI treatment of caffeine tended to exert neuroprotective effects at early and prolonged stages of bTBI respectively. Up-regulation of adenosine A1 receptor expression might contribute to the favorable effects of chronic caffeine consumption.</p><p><b>CONCLUSION</b>Since caffeinated beverages are widely consumed in both civilian and military personnel and are convenient to get, the results may provide a promising prophylactic strategy for blast-induced neurotrauma and the consequent cognitive impairment.</p>

Central-adenosine A1 receptor involved in the thermal regulation effect of YZG-330, a N6-substituted adenosine derivative, in mice / 药学学报

Adenosine receptors (AR) play an important role in the regulation processes for body temperature and vigilance states. During our previous studies, we noticed that aminophylline (a non-selective, blood-brain-barrier penetrably AR antagonist) could attenuate the effects of YZG-330 [(2R,3S,4R,5R)-2-(hydroxymethyl-5-(6-(((R)-1-phenylpropyl)amino)-9H-purin-9-yl)tetrahydrofuran-3, 4-diol] on lowering the body temperature. Hereby, we focused ourselves on the character of thermal regulation effect of YZG-330 in mice and tried to specify the receptor subtype via giving typical adenosine receptor antagonists. The results showed that both of the magnitude and lasting time of the effect that YZG-330 played on decreasing body temperature are in a dose-dependent manner: within the next 3 hour after intragastric administration (ig) of 0.25, 1 or 4 mg . kg-1 YZG-330, the extreme values on body temperature decreasing were (1.2 ± 0.3) °C, (3.6 ± 0.4) °C (P<0.001) and (7.4±0.5) °C (P<0.001), separately; whereas the duration that body temperature below 34 °C were 0, (10±5) and (153±4) min, separately. Adenosine A1 receptor (A1R) antagonist (DPCPX) could effectively reverse YZG-330's effect on decreasing body temperature, with intraperitoneal administration of DPCPX (5 mg . kg-1) 20 min prior than YZG-330 (4 mg.kg-1, ig), the extreme value on body temperature decreasing was (3.5 ± 0.7) °C (P<0.001), the duration that body temperature below 34 °C was (8±6) min (P<0.001). However, adenosine A2a receptor antagonist, SCH-58261, did not show any influence on the effects of YZG-330 at all. Combined with the fact that 8-SPT (a non-selective, blood-brain-barrier impenetrably AR antagonist) did not reverse the effect of YZG-330, we come to the conclusion that central-adenosine A, receptor plays a significant role on the thermal regulation effect of YZG-330.

Effects of caffeine citrate on myelin basic protein in neonatal rats with hypoxic-ischemic brain damage / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the effects of caffeine citrate on myelin basic protein (MBP) expression in the cerebral white matter of neonatal rats with hypoxic-ischemic brain damage (HIBD) and the related mechanism.</p><p><b>METHODS</b>Forty-eight seven-day-old Sprague-Dawley neonatal rats were randomly assigned to 3 groups: sham operation (n=16), HIBD (n=16) and HIBD+caffeine citrate (n=16). The rats in the HIBD and HIBD+caffeine citrate groups were subjected to left common carotid artery ligation, and then were exposed to 80 mL/L oxygen and 920 mL/L nitrogen for 2 hours to induce HIBD. The rats in the sham operation group were only subjected to a sham operation, without the left common carotid artery ligation or hypoxia exposure. Caffeine citrate (20 mg/kg) was injected intraperitoneally before hypoxia ischemia (HI) and immediately, 24 hours, 48 hours and 72 hours after HI. The other two groups were injected intraperitoneally with an equal volume of normal saline at the corresponding time points. On postnatal day 12, the expression of MBP in the left subcortical white matter was detected by immunohistochemistry, and the levels of adenosine A1 receptor mRNA and A2a receptor mRNA in the left brain were detected by real-time PCR.</p><p><b>RESULTS</b>The expression of MBP in the left subcortical white matter in the HIBD group was lower than in the sham operation group (P<0.05). The MBP expression in the HIBD+caffeine citrate group was significantly higher than in the HIBD group, but was still lower than the sham operation group (P<0.05). Real-time PCR showed that the adenosine A1 receptor mRNA expression was significantly higher in the HIBD group than in the sham operation group, and it was significantly lower in the HIBD+caffeine citrate group than in the HIBD group (P<0.05).</p><p><b>CONCLUSIONS</b>Caffeine citrate can improve brain white matter damage following HIBD in neonatal rats and the protection mechanism might be related with the down-regulation of adenosine A1 receptor expression.</p>

In vivo and in vitro anti-natriuretic activity of twigs fraction from Dorstenia picta: a possible mechanism

The present study examine the in vivo effects of Dorstenia Picta [D. picta] on urinary volume and sodium excretion in streptozotocin-induced diabetic rats, and determine a possible mechanism by which the extract increased sodium transport in A6 cells monolayers. Administration of the plant extract at the dose of 150 mg/kg during two weeks decreased urinary volume and sodium excretion. In vitro study showed that, apical application of the plant extract at the dose of 100 micro g/mL does not significantly increase sodium transport, whereas basolateral administration provoked a significant [P<0.05] increase of sodium transport in a concentration-dependent manner. The plant extract increases the sodium transport by 69.93% versus 55.41% for insulin and 78.44% for adenosine after 30 min. Preincubation of A6 cells monolayers with inhibitor of all adenosine receptors completely suppressed adenosine and plant extract stimulated sodium transport. Interesting is that, the A1 inhibitor receptor [DPCPX], at 100 nM completely abolished the effect of plant extract. The plant extract increased sodium transport by increase PI3-kinase activity and this effect is strongly inhibited by LY-294002. These data also suggest that, the twigs methanol fraction from Dorstenia picta increase sodium transport via PI 3-kinase pathway and requires A1 adenosine receptor

Advance in studies on effect of paeoniflorin on nervous system / 中国中药杂志

Paeoniflorin (PF) is the chief active component of paeonia, with diverse pharmacological actions and wide application. Recently, the effect of PF on nervous system has attracted increasingly more attention. According to current study findings, PF can ameliorate the decline of memory and learning capacities in many dementia model animals, and have effect in protecting the cerebral ischemia injury, treating Parkinson's disease, reliving pain and improving neural synapse plasticity. Thought its mechanism has not been clarified, current findings show that adenosine A1 receptor plays an important role, while M cholinergic receptor, opiate receptor, calcium ion channel and NF-KB may also play a part in paeoniflorin's effect on nervous system.

Stimulation of adenosine A1 receptor attenuates angiotensin II induced myocardial hypertrophy in neonatal rats via the extracellular signal-regulated kinase signal pathways / 中华心血管病杂志

<p><b>OBJECTIVE</b>To observe the impact of adenosine A1 receptor stimulation on extracellular signal-regulated kinase 1/2 (ERK1/2) signal pathways on angiotensin II (AngII) stimulated cardiomyocytes of neonatal rats in vitro.</p><p><b>METHODS</b>Cardiomyocytes of neonatal rats were cultured in vitro. Cardiomyocytes hypertrophy was induced by AngII (0.1 µmol/L). The antihypertrophic effect of adenosine A1 receptor stimulation via adenosine A1 receptor agonist R-PIA (1 µmol/L) was observed in the presence or absence of ERK1/2 inhibitor 1, 4-Diamino-2, 3-dicyano-1, 4-bis(o-aminophenylmercapto) butadiene (U0126) 1 µmol/L, PKC inhibitor Ro-31-8220 (50 nmol/L), and pertussis toxin (PTX, 5 mg/L). The total protein content was assayed by the method of Lowry. The expression of mRNA of atrial natriuretic peptide (ANP) was determined by RT-PCR. [Ca(2+)]i was measured by confocal microscope using Fluo-3/AM as fluorescent indicator. The relative expression of ERK1/2 was determined by Western blot.</p><p><b>RESULTS</b>Compared with normal control group, AngII induced significant cardiomyocyte hypertrophy. Compared with AngII group, R-PIA significantly inhibited AngII-induced increase of the protein content, cardiomyocytes volume and expression of ERK1/2, calcium ion fluorescence intensity, similar as U0126 and Ro-31-8220. The inhibitory effects on AngII induced cardiomyocytes hypertrophy of R-PIA were lost when preincubated with PTX.</p><p><b>CONCLUSION</b>Adenosine A1 receptor can inhibit AngII induced cardiomyocyte hypertrophy through downregulating ERK signal pathways and reducing intracellular Ca(2+).</p>

Intracerebroventricular administration of adenosine A1 receptor antisense oligodeoxynucleotide inhibites the neuroprotective effect of the cerebral ischemic preconditioning in rats / 中国应用生理学杂志

<p><b>AIM</b>To further explore the role of adenosine A1 receptor in the neuroprotective effect of cerebral ischemic preconditioning, the present study was undertaken to observe the effect of inhibiting expression of adenosine Al receptor with adenosine A1 receptor antisense oligodeoxynucleotide (ARA1 As-ODN) on the neuroprotective effect of cerebral ischemic preconditioning against delayed neuronal death (DND) normally induced by lethal brain ischemia.</p><p><b>METHOD</b>The rat 4-vessel occlusion global cerebral ischemic model was used. Forty-eight male Wistar rats with permanent occlusion of the bilateral vertebral arteries were divided into 8 groups: Sham, CIP, brain ischemic insult, CIP + brain ischemic insult, Distilled water + CIP + brain ischemic insult, ARA1 As-ODN, ARA1 As-ODN +CIP, ARA1 As-ODN+ CIP + brain ischemic insult(two doses of 10 nmol/5 microl and 20 nmol/5 microl were used) groups. ARA1 As-ODN was dissolved in distilled water and injected into the right lateral cerebral ventricle. To illustrate the profile of DND, histological grade (HG) and neuronal density (ND) in the CA1 region of the hippocampus were examined 7 d after the sham operation or the last time of ischemia under thionin staining.</p><p><b>RESULTS</b>The HG and ND in CIP group were similar to those in sham group. Brain ischemic insult induced obvious DND as represented with the increase in HG and decrease in ND significantly (P < 0.05 vs. sham and CIP groups). In CIP + ischemic insult group,no obvious DND was observed,which indicated that CIP protected pyramidal neurons against the ischemic insult.While the administration of ARA1 As-ODN in ARA1 As-ODN + CIP + brain ischemic insult group caused obvious increase in HG and decrease in ND compared with CIP + brain ischemic insult group (P < 0.05) in a dose dependent manner,which indicated that the neuroprotective effect of CIP against DND of hippocampal pyramidal neurons normally induced by ischemic insult was inhibited by the administration of ARA1 As-ODN.</p><p><b>CONCLUSION</b>The results further demonstrate the association of up-regulation of adenosine A1 receptors with the induction of CIP-mediated BIT.</p>

The Interaction of Gabapentin and N(6)-(2-phenylisopropyl)-adenosine R-(-)isomer (R-PIA) on Mechanical Allodynia in Rats with a Spinal Nerve Ligation

We examined the antiallodynic interaction between gabapentin and adenosine A1 receptor agonist, N(6)-(2-phenylisopropyl)-adenosine R-(-)isomer (R-PIA), in a rat model of nerve ligation injury. Rats were prepared with ligation of left L5-6 spinal nerves and intrathecal catheter implantation for drug administration. Mechanical allodynia was measured by applying von Frey filaments. Gabapentin and R-PIA were administered to obtain the dose-response curve and the 50% effective dose (ED50). Fractions of ED50s were administered concurrently to establish the ED50 of the drug combination. The drug interaction between gabapentin and R-PIA was analyzed using the isobolographic method. Adenosine A1 receptor antagonist was administered intrathecally to examine the reversal of the antiallodynic effect. Locomotor function changes were evaluated by rotarod testing. Intrathecal gabapentin and R-PIA and their combination produced a dose-dependent antagonism against mechanical allodynia without severe side effects. Intrathecal gabapentin synergistically enhanced the antiallodynic effect of R-PIA when coadministered. There were no significant changes in rotarod performance time, except gabapentin 300 microgram. In the combination group, the maximal antiallodynic effect was reversed by A1 adenosine receptor antagonist. These results suggest that activation of adenosine A1 receptors at the spinal level is required for the synergistic interaction on the mechanical allodynia.

A Polymorphism (rs10920568, A102A) of Adenosine A1 Receptor (ADORA1) Gene is Associated with Schizophrenia in Korean Population

Adenosine A1 receptor (ADORA1) has a neuromodulatory activity in early stage of brain development. Recent studies have been suggested that a deficit in adenosinergic function may be a key factor in the pathophysiology of schizophrenia. To determine the genetic association between ADORA1 gene polymorphism and schizophrenia in Korean population, we genotyped single nucleotide polymorphism (SNP) (rs10920568, A102A, exon5) in the ADORA1 gene by using the direct sequencing. Among SNPs in the coding region of ADORA1, only one synonymous SNP's heterozygosity (rs10920568) is more than 0.05. Three hundred three control and 284 schizophrenia subjects were recruited. For the analysis of genetic data, EM algorithm, SNPStats, SNPAnalyzer, and Helixtree programs were used. Multiple logistic regression analysis with the codominant, dominant, and recessive models was performed. The genotype frequencies of rs10920568 showed statistically significant difference between schizophrenic patients and healthy control subjects. The rs10920568 SNP of ADORA1 was weakly associated with schizophrenia in the dominant model (p=0.04, odds ratio=0.70, 95% confidence interval =0.50~0.98). The result suggests that the ADORA1 gene may be associated with schizophrenia.

The Effects of Intrathecal Adenosine A1 Receptor Agonists (R-PIA) on the Morphine Tolerance in a Rat Model of Postoperative Pain / 대한마취과학회지

BACKGROUND: Analgesic tolerance to opioids has been described in both experimental and clinical conditions, which may limit their clinical utility. This study investigated the effects of intrathecal adenosine A1 receptor agonist (R-PIA) on spinal morphine tolerance. METHODS: SD rats were given intrathecal injections of saline 10microliter, R-PIA 10microgram, morphine 10microgram, or R-PIA plus morphine combinations for 7 days (R-PIA given for days 1-7; days 1-3; or days 5-7). Antiallodynic testing using von Frey filaments was carried out before and 30 minutes after the drug injection. On day 8, an antiallodynic dose-response curve was constructed and the 50% effective dose (ED(50)) for morphine (given alone) was calculated for each study group. RESULTS: The coinjection group of R-PIA with morphine blocked the development of tolerance, as shown by the preservation of morphine antiallodynia over 7 days the concomitant decrease in the ED(50) values on day 8, compared with the morphine-alone group. Although additive analgesia over days 1-7 cannot be ruled out, the reductions of the ED(50) in the R-PIA and morphine combination group suggest some suppression of tolerance. CONCLUSIONS: These results suggest that intrathecal R-PIA prevents the development of spinal opioid tolerance. Future studies will be needed to examine the respective roles of supraspinal and peripheral sites of R-PIA and morphine interaction, and to investigate the mechanisms underlying the action of R-PIA on opioid tolerance.

Adenosine A1 receptor-mediated inhibition of in vitro prolactin secretion from the rat anterior pituitary

In previous studies, we demonstrated biphasic purinergic effects on prolactin (PRL) secretion stimulated by an adenosine A2 agonist. In the present study, we investigated the role of the activation of adenosine A1 receptors by (R)-N6-(2-phenylisopropyl)adenosine (R-PIA) at the pituitary level in in vitro PRL secretion. Hemipituitaries (one per cuvette in five replicates) from adult male rats were incubated. Administration of R-PIA (0.001, 0.01, 0.1, 1, and 10 æM) induced a reduction of PRL secretion into the medium in a U-shaped dose-response curve. The maximal reduction was obtained with 0.1 æM R-PIA (mean ± SEM, 36.01 ± 5.53 ng/mg tissue weight (t.w.)) treatment compared to control (264.56 ± 15.46 ng/mg t.w.). R-PIA inhibition (0.01 æM = 141.97 ± 15.79 vs control = 244.77 ± 13.79 ng/mg t.w.) of PRL release was blocked by 1 æM cyclopentyltheophylline, a specific A1 receptor antagonist (1 æM = 212.360 ± 26.560 ng/mg t.w.), whereas cyclopentyltheophylline alone (0.01, 0.1, 1 æM) had no effect. R-PIA (0.001, 0.01, 0.1, 1 æM) produced inhibition of PRL secretion stimulated by both phospholipase C (0.5 IU/mL; 977.44 ± 76.17 ng/mg t.w.) and dibutyryl cAMP (1 mM; 415.93 ± 37.66 ng/mg t.w.) with nadir established at the dose of 0.1 æM (225.55 ± 71.42 and 201.9 ± 19.08 ng/mg t.w., respectively). Similarly, R-PIA (0.01 æM) decreased (242.00 ± 24.00 ng/mg t.w.) the PRL secretion stimulated by cholera toxin (0.5 mg/mL; 1050.00 ± 70.00 ng/mg t.w.). In contrast, R-PIA had no effect (468.00 ± 34.00 ng/mg t.w.) on PRL secretion stimulation by pertussis toxin (0.5 mg/mL; 430.00 ± 26.00 ng/mg t.w.). These results suggest that inhibition of PRL secretion after A1 receptor activation by R-PIA is mediated by a Gi protein-dependent mechanism.

El poscondicionamiento isquémico reduce el tamaño del infarto por activación de los receptores de adenosina en animales normales e hipercolesterolémicos / Ischemic postconditionning reduces infarct size by activating adenosine receptors in animals with normal and high cholesterol levels

El poscondicionamiento isquémico (Poscon) reduce el tamaño del infarto en animales normales. Sin embargo, el efecto de este mecanismo de protección en animales hipercolesterolémicos se desconoce. El objetivo del presente estudio fue determinar si el Poscon reduce el tamaño del infarto en animales hipercolesterolémicos. Un segundo objetivo fue evaluar si los receptores A1 participan en el mecanismo de protección del Poscon. Se perfundieron corazones aislados e isovolúmicos de conejos normales e hipercolesterolémicos según técnica de Langendorff y se sometieron a 30 min de isquemia global y 30 min de reperfusión (grupo 1 [G1]). En el grupo 2 (G2) se provocaron dos episodios de reperfusión/isquemia (30 seg cada uno, Poscon) luego de 30 min de isquemia. En el grupo 3 (G3) se repitió el protocolo del G2, pero se administró un bloqueante A1 (DPCPX, 200 nM). En los grupos 4, 5 y 6 (G4, G5 y G6), constituidos por animales que fueron alimentados con una dieta rica en colesterol (1 por ciento) durante 4 semanas, se repitieron todos estos protocolos experimentales. Se midieron la presión desarrollada del VI (PDVI), la presión diastólica final del VI (PDFVI) y el tamaño del infarto utilizando TTC. El tamaño del infarto en el G1 y el G4 fue del 15,7 por ciento ± 1,5 por ciento y del 24,4 por ciento ± 3,1 por ciento, respectivamente. El Poscon redujo el área de infarto hasta alcanzar el 5,5 por ciento ± 0,9 por ciento en animales normales y el 5,6 por ciento ± 1,6 por ciento en los hipercolesterolémicos (p < 0,05 versus G1 y G4). La administración de DPCPX abolió el efecto protector del Poscon en ambos grupos de animales (G3: 15,1 ± 1,7 y G6: 21,2 ± 1,9). El Poscon reduce el tamaño del infarto en animales normales e hipercolesterolémicos a través de la activación de los receptores A.

[Anti-tumor evaluation of adenosine and cyclohexyladenosine [A1 receptor selective agonist] using potato disc assays]

In this study, adenosine and cyclohexyladenosine [CHA] were tested for possible anti-tumor activity using potato disc assays. MIC of adenosine and CHA were determined using microplate method. In potato disc assay, discs were cut of potato with specific diameter and transferred on 1.5% agar under a laminar air cabinet. 50 ?l of a mixture containing suspension of Agrobacterium tumefaciens and the solution of agents were inoculated on potato discs in plates. The plates were incubated in 25 °C for 21 days until the tumors were counted. Adenosine and CHA did not show any anti-bacterial activity. The IC50 values of adenosine and CHA against tumor were 93.78 and 19.56 microM, respectively. DPCPX [A1 selective adenosine receptor antagonist] inhibited the anti-tumor activity of adenosine and CHA, while itself did not show any effect against potato disc tumors. This study indicates that adenosine and CHA have anti-tumor activity, and this effect is mediated via A1 receptor exists in potato cell or A. tumefaciens