YZG-330 regulates the TRPM8 ion channel through the P38 MAPK signaling pathway to reduce body temperature in mice / 药学学报

Preliminary research in our laboratory found that compound YZG-330 can reduce mouse body temperature, which could be blocked by adenosine A1 receptor (A1R) antagonist DPCPX. Based on the downstream signaling pathway of the A1R, the mechanism by which YZG-330 lowers body temperature was further studied. The pharmacodynamics of YZG-330 was evaluated by measuring the rectal temperature; expression of the transient receptor potential (TRP) ion channel, the P38 protein and its phosphorylated form in mouse hypothalamic homogenate were detected by Western blotting. A Ca2+ fluorescent probe, Fluo-3AM, was added to cells to detect the effect of YZG-330 on the Ca2+ content of mouse hypothalamic cells. YZG-330 dose-dependently reduced the body temperature in mice, and the selective P38 inhibitor SB-203580 (20 mg·kg-1, i.p.) significantly inhibited the hypothermic effect of YZG-330. A TRPM8 antagonist 2 (0.1 μg per mouse, i.c.v.) markedly attenuated the hypothermic effect of YZG-330 (0.25 or 1 mg·kg-1, i.p.). YZG-330 (2 mg·kg-1, i.p.) significantly increased the phosphorylation of P38, an effect that could be attenuated by the A1R antagonist DPCPX (5 mg·kg-1, i.g.) in mouse hypothalamus. In addition, YZG-330 also prominently enhanced the expression of TRPM8, which could be blocked by SB-203580; YZG-330 (0.1-10 μmol·L-1) increased intracellular Ca2+ concetration in mouse hypothalamic cells in a dose-dependent manner, and was inhibited by the A1R inhibitor DPCPX (0.5 and 1 μmol·L-1) and TRPM8 antagonist 2 (1 μmol·L-1). In conclusion, YZG-330 exerts its hypothermic effect by activating the A1R to promote the phosphorylation of P38 protein and thereby up-regulating the expression and activity of the TRPM8 ion channel, resulting in increased intracellular Ca2+ concentration to stimulate mouse hypothalamus cells to down-regulate body temperature. All animal experiments were approved by the Ethics Committee of the Institute of Materia Medica, Chinese Academy of Medical Sciences.

Spinal transcription factor GATA4 mediated adenosine A1 receptor activation contributes to electroacupuncture analgesia in neuropathic pain rats / 针刺研究

OBJECTIVE: To investigate the effect of electroacupuncture (EA) on pain behaviors and expression of spinal transcription factor GATA-binding Protein 4 (GATA4) and adenosine A1 receptor in neuropathic pain rats, so as to explore its mechanism underlying pain relief. METHODS: The present study includes 2 parts. In the first part, 18 SD rats were randomly divided into control, adenovirus short-hairpin interference RNA for GATA4 (AV-shGATA4 RNA) and adenovirus empty vector (AV-control short-hairpin RNA, AV-shCTRL) groups, with 6 rats in each group. The expression of GATA4 protein in the lumbar spinal cord (L4-L6) was detected to evaluate the transfection efficiency of AV-shGATA4 RNA (silencing GATA4 expression). In the second part, thirty SD rats were randomly divided into 5 groups, namely sham operation, CCI model, EA, EA+AV-shGATA4 RNA, and EA+AV-shCTRL groups, with 6 rats in each group. The neuropathic pain model was established by chronic constriction injury (CCI) of the right sciatic nerve. On the 7th day following modeling, EA was applied to the right "Zusanli"(ST36) and "Taichong"(LR3) (1 mA，2 Hz /100 Hz) for 30 min. Rats of the EA+AV-shGATA4 RNA and EA+AV-shCTRL groups received intrathecal injection of AV-shGATA4 RNA and AV-shCTRL(1×1011 PFU/mL，10 μL)at the spinal L4-L6 segments, separately, 48 h before EA intervention. The mechanical pain threshold and thermal pain threshold of the affected limb were detected before molding, 7 days following molding and 60 min after EA. The expressions of adenosine A1 receptor and GATA4 protein in the spinal cord (L4-L6) were detected by Western blot. RESULTS: Outcomes of the first part showed that compared with the control group, no significant changes were found in the mechanical and thermal pain thresholds in both AV-shCTRL and AV-shGATA4 RNA groups and in the expression of spinal GATA4 protein of the AV-shCTRL group (P＞0.05). The expression of spinal GATA4 protein of the AV-shGATA4 RNA group was significantly lower than that of the AV-shCTRL group (P 0.05). On the 7th day following modeling, the mechanical and thermal pain thresholds were significantly lowered in compa-rison with their own pre-modeling of each group and with the sham operation group (P0.05), suggesting a critical involvement of GATA4 in EA analgesia. The expression levels of adenosine A1 receptor and GATA4 protein were significantly increased in the model group than in the sham operation group (P0.05), suggesting that the effects of EA in up-regulating the expression of A1 receptor and GATA4 were eliminated after silencing GATA4 protein. CONCLUSION: EA of ST36 and LR3 can relieve pain by increasing the expression of adenosine A1 receptor of the lumbar spinal cord in neuropathic pain rats, which is probably mediated by GATA4 protein.

The research progress on the mechanism of adenosine A1 receptor-mediated calcitonin gene-related peptide to relieve migraine

Currently, the pathogenesis of migraine is unclear. The trigeminal vascular reflex theory is the dominant pathogenesis theory, and its core parts are neurogenic inflammation and pain sensitisation. Calcitonin gene related peptide (CGRP) is the most powerful vasodilating peptide in brain circulation. It is also a marker of trigeminal nerve microvascular activation that plays a synergistic role in the pathogenesis of migraine. Adenosine A1 receptor (A1R) can inhibit the release of CGRP in the trigeminal nerve vascular system to alleviate migraine by mediating adenosine. This review summarises the progress of research on the alleviation of migraine by using A1R-mediated CGRP.

The Advance of Escitalopram's Drug-induced QTc Prolongation / 中国药学杂志

Escitalopram, a selective serotonin re-uptake inhibitor (SSRI) antidepressant which is the (S)-enantiomer of citalopram, is worldwide used for the treatment of depressive and anxious disorders in clinical practice, however, recent data have indicated that high therapeutic escitalopram doses may cause the potential of QTc prolongation effect, which is a predisposing factor for arrhythmia. Nevertheless, in March 2012, the Food and Drug Administration (FDA) issued a safety bulletin advising the daily dosage of escitalopram should be restricted to a maximum of 20 mg daily in healthy adults and 10 mg maximum in high risk patients (eg>60 years of age). In this review, we aimed to investigate what factors can affect and how escitalopram gives rise to QTc prolongation.

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.

Cordycepin protects against β-amyloid and ibotenic acid-induced hippocampal CA1 pyramidal neuronal hyperactivity

Cordycepin exerts neuroprotective effects against excitotoxic neuronal death. However, its direct electrophysiological evidence in Alzheimer's disease (AD) remains unclear. This study aimed to explore the electrophysiological mechanisms underlying the protective effect of cordycepin against the excitotoxic neuronal insult in AD using whole-cell patch clamp techniques. β-Amyloid (Aβ) and ibotenic acid (IBO)-induced injury model in cultured hippocampal neurons was used for the purpose. The results revealed that cordycepin significantly delayed Aβ + IBO-induced excessive neuronal membrane depolarization. It increased the onset time/latency, extended the duration, and reduced the slope in both slow and rapid depolarization. Additionally, cordycepin reversed the neuronal hyperactivity in Aβ + IBO-induced evoked action potential (AP) firing, including increase in repetitive firing frequency, shortening of evoked AP latency, decrease in the amplitude of fast afterhyperpolarization, and increase in membrane depolarization. Further, the suppressive effect of cordycepin against Aβ + IBO-induced excessive neuronal membrane depolarization and neuronal hyperactivity was blocked by DPCPX (8-cyclopentyl-1,3-dipropylxanthine, an adenosine A₁ receptor-specific blocker). Collectively, these results revealed the suppressive effect of cordycepin against the Aβ + IBO-induced excitotoxic neuronal insult by attenuating excessive neuronal activity and membrane depolarization, and the mechanism through the activation of A₁R is strongly recommended, thus highlighting the therapeutic potential of cordycepin in AD.

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.

Effect of Electroacupuncture on the Expression of Adenosine A1Receptor in Hypothalamus and Spinal Cord of Adjuvant Arthritis Rats / 上海针灸杂志

Objective To observe the effect of adenosine A1 receptor on pain and electroacupuncture analgesia, and to explore the action mechanism of electroacupuncture in analgesia.Method Adjuvant arthritis rats were taken as the study subjects. 24 rats were randomized into a normal group, a model group and an electroacupuncture (EA) group, 8 rats in each group. The pain threshold was evaluated by using thermal radiation method, immunohistochemical method and real-time fluorescence quantitative PCR were adopted to observe the expression of adenosine A1 receptor in hypothalamus and spinal cord.Result One day after modeling, the pain thresholds of right hind paw in the model group and EA group were significantly changed compared to that before modeling in the same group (P<0.01). The pain thresholds of right hind paw in the model group and EA group were significantly different from that in the normal group one day after modeling (P<0.01). 7 d after modeling, the pain threshold of right hind paw in the model group was still significantly lower than that before modeling in the same group (P<0.01), and it was significantly different from that in the normal group and EA group (P<0.01). The pain threshold was significantly enhanced in the EA group 7 d after modeling, and was significantly different from that of 1 d after modeling in the same group (P<0.01). The positive cell expression was lower in the model group and was significantly different from that in the normal group (P<0.01). The expression of adenosine A1 receptor in the EA group was markedly higher than that in the model group (P<0.01). The expression of adenosine A1 receptor in hypothalamus and spinal cord of the model group was significantly lower than that of the normal group (P<0.01). The expression of adenosine A1 receptor in hypothalamus and spinal cord of EA group was markedly higher than that of the model group (P<0.01).Conclusion EA can up-regulate the expression of adenosine A1 receptor in hypothalamus and spinal cord of adjuvant arthritis rats.

Proliferation and activation of acetaldehyde-induced HSC-T6 cells through RNA inference targeting adenosine A1 and A2 A receptors / 中国药理学通报

Aim To investigate the influence of down-regulating adenosine A1 receptor and adenosine A2 A receptor gene expression on proliferation and activation of acetaldehyde-induced hepatic stellate cell-T6 cells through siRNA. Methods Alcoholic liver fibrosis in vitro model was constructed by inducing HSC-T6 cells with acetaldehyde. siRNA targeting A1R and A2AR were designed and synthesized according to its mRNA. The siRNA was transfected into rat HSC-T6 cells by li-posome LipofectamineTM 2000. HSC cell proliferation was measured by MTT. The mRNA levels of A1R, A2AR, α-SMA, Collagen I in the supernatant of the cell culture were measured by Quantitative Real-Time PCR. The protein levels of A1R, A2AR, α-SMA, Collagen I were measured by Western blot. Results A1 R and A2 AR siRNA effectively inhibited the cell proliferation, and they also significantly decreased the levels of A1R, A2AR,α-SMA, Collagen I, suggesting that A1 R and A2 AR might be potential target genes in the alcoholic liver fibrosis. Conclusions Silencing A1 R or A2 AR by RNAi can significantly inhibit the HSC proliferation, A1R and A2AR may be potential therapeutic target genes for alcoholic liver fibrosis.

Metallothionein mediates cardioprotection induced by delayed preconditioning with adenosine A1 receptor agonist in rabbits / 中南大学学报(医学版)

Objective To investigate the protective effect of adenosine A1 receptor agonist (2-chloro-N6-cyclopentyladenosine, CCPA) delayed preconditioning on myocardial ischemia reperfu-sion injury and the potential mechanism in rabbits. Methods Thirty New Zealand male white rabbits were randomly assigned to 3 groups:a control group, an I/R group, and a CCPA group. CCPA group was given CCPA 0.1 mg/kg before the myocardial ischemia. Twenty-four hours later I/R group and CCPA group underwent 40 min of coronary occlusion followed reperfusion for 2 h. At the end of the reperfusion, blood samples were taken from the arterial line for determining the plasma level of malondialdhyde and superoxide dismutase activity. The infarct size and area at risk were de-fined by Evans and TIC staining. The heart was harvested and levels of metallothionein (MT) were determined by Western blot, and ultrastructures were observed under the electron microscope. Results The MT level of CCPA group was significantly higher than that of the I/R group (P<0.05). CCPA significantly reduced the infarct size (22.1%±3.8% in the CCPA group) of the left yen-tricular area at risk as compared with the control (41.8%±4.3% in the I/R group,P<0.05). The injury of I/R group was worse than that of the CCPA group under the light microscope. CCPA group had higher superoxide dismutase and lower malondialdhyde than those of the I/R group. Con-clusion CCPA can increase the level of metallothionein during ischemia-reperfusion, which may be part of the molecular mechanism of CCPA delayed preconditioning on cardioprotection.

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.

Protective Roles of Adenosine A1 Receptor Agonist and KATP Channel Opener in Adriamycin induced Cardiac Toxicity / 체질인류학회지

Although adriamycin is a potent chemotherapeutic agent, it elicits serious adverse effects, including cardiac toxicity. Evidence suggests that congestive heart failure induced by adriamycin is mediated by oxidative stress. We investigated whether regulators of adenosine A1 receptor and KATP channel, which have been demonstrated to mediate protective effects of ischemic -preconditioning in myocardium, are able to modulate adriamicin -induced impairment of cardiomyocyte. To study the effect of antioxidant, adenosine A1 receptor agonist & antagonist and KATP channel agonist & antagonist, ICR mice were pretreated with Cu,Zn -SOD, dimethyl thiourea, RPIA (R (-)N6 -(2 -Phenylisopropropyl)- adenosine, adenosine A1 receptor agonist), 8 -CPDPX (8 -Cyclopentyl -1, 3 -dipropylxanthine, adenosine A1 receptor antagonist), Pinacidil (KATP channel opener) and glibenclamide (KATP channel closer), followed by i.p injection with adriamycin. Mice were sacrificed day 1 or day 4 after adriamycin injection and cardiac toxicity was accessed by measurement of creatine phosphokinase (CK) levels in serum, immunohistochemistry using anti -Bcl -2 antibody and TUNEL histochemical assay. As expected, pretreatment of mice with Cu, Zn -SOD and DMTU reduced the frequency of TUNEL positive cells, indicating antioxidants protected cardiocytes from adriamycin -induced apoptosis. Interestingly, pretreatment with RPIA and pinacidil induced a significant decrease in adriamycin -induced cytotoxicity, whereas 8 -CPDPX and glibenclamide generated the opposite results. In Bcl -2 immunohistochemistry, an increased expression of Bcl -2 was found in all ADR treated groups, especially in glibenclamide pretreated group, and 8 -CPDPX pretreated groups, but Bcl -2 failed to protect myocytes from apoptosis. All ADR treated groups exhibited elevated levels of serum CK, compared with nomal controls, especially mice sacrificed at day 4 than those at day 1, and showed similar patterns of TUNNEL assay, reflecting heart tissue damages. This observation implicated cytoprotective roles of RPIA and pinacidil against adriamycin -induced cardiac toxicity. In conclusion, these results demonstrated that adriamycin -induced cardiotoxicity was associated with the generation of reactive oxygen species and that regulators including SOD, DMTU, RPIA and pinacidil elicited protective effects on this toxicity. In particular, pinacidil, the KATP channel opener, was more effective than RPIA, the adenosine A, receptor agonist, to attenate the adriamycin -induced cardiac toxicity.

Effects of adenosine A_1 receptor antagonist on the hippocampal BDNF protein expression and endoplasmic reticulum content of rats / 中国药理学通报

Aim To study the effect of blocking adenosine A_1 receptors on BDNF protein expression and the endoplasmic reticulum(ER) content of the rat hippocampus.Methods The effect of DPCPX on BDNF protein expression in granular cells of the rat hippocampus was observed using immunohistochemical method,and the effect of DPCPX on ER in neurons of the rat hippocampus was observed with transmission electron microscope.Results DPCPX(0.1 mg?kg~(-1),ip,15 d) significantly increased the number of BDNF positive cells in hippocampus granular cells.DPCPX(0.5 mg?kg~(-1),ip,15 d) significantly increased both the levels of BDNF protein and the number of BDNF positive cells in hippocampus granular cells(P

Protection of adenosine A1 receptor agonist delayed preconditioning for myocardial ischemia reperfusion injury in rabbits / 重庆医科大学学报

Objective:To investigate the protection mechanism of adenosine A1 receptor agonist(2-chloro-N6-cyclopentyladenosine, CCPA)delayed preconditioning for rabbit myocardium during ischemia reperfusion.Methods:Thirty New Zealand male white rabbits were randomly assigned to Sham group,I/R group and CCPA group,with ten in each.Group CCPA was given CCPA 0.1 mg/kg before myocardial ischemia.Twenty-four hours later the I/R and CCPA underwent 40 min of coronary occlusion followed by 2 h of reperfusion.Blood samples were taken from arterial line at 20 min before occlusion(T)1,20 min after occlusion(T2),40 min after occlusion(T)3,1 h after reperfusion(T)4and 2 h after reperfusion(T)5for determination of the plasma levels of IL-10.At the end of the reperfusion,infarct size(IS)and area at risk(AAR)were defined by Evans blue and TTC staining.The heart was harvested and levels of the HSP70 were determined by Western blot analysis,and ultrastructures were observed under the electron microscopy.Results:The IL-10 and HSP70 levels of group CCPA was higher than those of group I/R.The CCPA(P