Role of Cannabinoid CB1 Receptor in Object Recognition Memory Impairment in Chronically Rapid Eye Movement Sleep-deprived Rats

Objective We aimed to investigate whether antagonism of the cannabinoid CB1 receptor(CB1R)could affect novel object recognition(NOR)memory in chronically rapid eye movement sleep-deprived(RSD)rats.Methods The animals were examined for recognition memory following a 7-day chronic partial RSD paradigm using the multiple platform technique.The CB1R antagonist rimonabant(1 or 3 mg/kg,i.p.)was administered either at one hour prior to the sample phase for acquisition,or immediately after the sample phase for consolidation,or at one hour before the test phase for retrieval of NOR memory.For the reconsolidation task,rimonabant was administered immediately after the second sample phase.Results The RSD episode impaired acquisition,consolidation,and retrieval,but it did not affect the reconsolidation of NOR memory.Rimonabant administration did not affect acquisition,consolidation,and reconsolidation;however,it attenuated impairment of the retrieval of NOR memory induced by chronic RSD.Conclusions These findings,along with our previous report,would seem to suggest that RSD may affect different phases of recognition memory based on its duration.Importantly,it seems that the CB1R may,at least in part,be involved in the adverse effects of chronic RSD on the retrieval,but not in the acquisition,consolidation,and reconsolidation,of NOR memory.

Signal Peptide and Denaturing Temperature are Critical Factors for Efficient Mammalian Expression and Immunoblotting of Cannabinoid Receptors

Many researchers employed mammalian expression system to artificially express cannabinoid receptors, but immunoblot data that directly prove efficient protein expression can hardly be seen in related research reports. In present study, we demonstrated cannabinoid receptor protein was not able to be properly expressed with routine mammalian expression system. This inefficient expression was rescued by endowing an exogenous signal peptide ahead of cannabinoid receptor peptide. In addition, the artificially synthesized cannabinoid receptor was found to aggregate under routine sample denaturing temperatures (i.e.,≥95°C), forming a large molecular weight band when analyzed by immuno-blotting. Only denaturing temperatures ≤75°C yielded a clear band at the predicted molecular weight. Collectively, we showed that efficient mammalian expression of cannabinoid receptors need a signal peptide sequence, and described the requirement for a low sample denaturing temperature in immuno-blot analysis. These findings provide very useful information for efficient mammalian expression and immuno-blotting of membrane receptors.

Inhibition of 5-HT_3 Receptors-activated Currents by Cannabinoids in Rat Trigeminal Ganglion Neurons

This study investigated the modulatory effect of synthetic cannabinoids WIN55,212-2 on 5-HT3 receptor-activated currents (I5-HT3) in cultured rat trigeminal ganglion (TG) neurons using whole-cell patch clamp technique. The results showed that: (1) The majority of examined neurons (78.70%) were sensitive to 5-HT (3–300 μmol/L). 5-HT induced inward currents in a concentration-dependent manner and the currents were blocked by ICS 205-930 (1 μmol/L), a selective antagonist of the 5-HT3 receptor; (2) Pre-application of WIN55,212-2 (0.01–1 μmol/L) significantly inhibited I5-HT3 reversibly in concentration-dependent and voltage-independent manners. The concentra-tion-response curve of 5-HT3 receptor was shifted downward by WIN55,212-2 without any change of the threshold value. The EC50 values of two curves were very close (17.5±4.5) mmol/L vs. (15.2±4.5) mmol/L and WIN55,212-2 decreased the maximal amplitude of I5-HT3 by (48.65±4.15)%; (3) Neither AM281, a selective CB1 receptor antagonist, nor AM630, a selective CB2 receptor antagonist reversed the inhibition of I5-HT3 by WIN55,212-2; (4) When WIN55,212-2 was given from 15 to 120 s before 5-HT application, inhibitory effect was gradually increased and the maximal inhibition took place at 90 s, and the inhibition remained at the same level after 90 s. We are led to concluded that-WIN55,212-2 inhibited I5-HT3 significantly and neither CB1 receptor antagonist nor CB2 receptor antagonist could reverse the inhibition of I5-HT3 by WIN55,212-2. Moreover, WIN55,212-2 is not an open channel blocker (OCB) of 5-HT3 receptor. WIN55,212-2 significantly inhibited 5-HT-activated currents in a non-competitive manner. The inhibition of I5-HT3 by WIN55,212-2 is probably new one of peripheral analgesic mechanisms of WIN55,212-2, but the mechanism by which WIN55,212-2 inhibits I5-HT3 warrants further investigation.

Activating cannabinoid CB1 receptors in a newly identified neural circuit ameliorates depressive-like behaviors in mice

With the support by the National Natural Science Foundation of China,the research team led by Prof.Li XiaoMing(李晓明)at the Center for Neuroscience,NHC and CAMS Key Laboratory of Medical Neurobiology,Zhejiang University School of Medicine,uncovered the new circuit and molecular mechanisms of depression,which was published in Nature Medicine(2019,25(2):337-349).

Cannabinoid CB_(2) receptors and spinal microglia are implicated in tingenone-mediated antinociception in mice

Objective:To investigate the antinociceptive effect of tingenone on inflammatory pain,as well as and the involvement of the cannabinoid receptors type 2(CB2)and spinal microglia in this process.Methods:Male Swiss mice were subjected to inflammatory pain induced by intraplantar injection of carrageenan.The nociceptive threshold was measured by von Frey filaments test.Tingenone was administered orally 60 min before carrageenan injection.To evaluate the involvement of CB2 receptor,endocannabinoids,and microglia,AM630(a CB2 receptor antagonist),MAFP(an inhibitor of an enzyme that hydrolyses endocannabinoids),and minocycline(a microglial inhibitor)were given intrathecally 20 min before tingenone administration.In addition,an immunofluorescence assay was used to evaluate CB2 receptor and CD11 B(a microglial marker)expression in the spinal cord dorsal horn.Results:Tingenone significantly reduced carrageenan-induced hyperalgesia,which was reversed by pretreatment with AM630.MAFP and minocycline potentiated and prolonged the tingenoneinduced antinociception.CD11 B expression was increased in the spinal cord dorsal horn of mice with inflammatory pain pretreated with tingenone,which was reduced by AM630,MAFP,and minocycline.Conclusions:CB2 receptors and endocannabinoids participate in the tingenone-induced antinociception which may involve the inhibition of microglia at spinal level.

Induction of Anxiety-Like Phenotypes by Knockdown of Cannabinoid Type-1 Receptors in the Amygdala of Marmosets

The amygdala is an important hub for regulating emotions and is involved in the pathophysiology of many mental diseases,such as depression and anxiety.Meanwhile,the endocannabinoid system plays a crucial role in regulating emotions and mainly functions through the cannabinoid type-1 receptor(CB1R),which is strongly expressed in the amygdala of non-human primates(NHPs).However,it remains largely unknown how the CB1Rs in the amygdala of NHPs regulate mental diseases.Here,we investigated the role of CB1R by knocking down the cannabinoid receptor 1(CNR1)gene encoding CB1R in the amygdala of adult marmosets through regional delivery of AAV-SaCas9-gRNA.We found that CB1R knockdown in the amygdala induced anxiety-like behaviors,including disrupted night sleep,agitated psychomotor activity in new environments,and reduced social desire.Moreover,marmosets with CB1R-knockdown had up-regulated plasma cortisol levels.These results indicate that the knockdown of CB1Rs in the amygdala induces anxiety-like behaviors in marmosets,and this may be the mechanism underlying the regulation of anxiety by CB1Rs in the amygdala of NHPs.

Role of cannabinoids in chronic liver diseases

Cannabinoids are a group of compounds acting pri-marily via CB1 and CB2 receptors.The expression of cannabinoid receptors in normal liver is low or absent.However,many reports have proven up-regulation of the expression of CB1 and CB2 receptors in hepatic myofibroblasts and vascular endothelial cells,as well as increased concentration of endocannabinoids in liver in the course of chronic progressive liver diseases.It has been shown that CB1 receptor signalling exerts profibrogenic and proinflammatory effects in liver tis-sue,primarily due to the stimulation of hepatic stellate cells,whereas the activation of CB2 receptors inhibits or even reverses liver fibrogenesis.Similarly,CB1 re-ceptor stimulation contributes to progression of liver steatosis.In end-stage liver disease,the endocannabi-noid system has been shown to contribute to hepatic encephalopathy and vascular effects,such as portal hypertension,splanchnic vasodilatation,relative pe-ripheral hypotension and probably cirrhotic cardiomy-opathy.So far,available evidence is based on cellular cultures or animal models.Clinical data on the effects of cannabinoids in chronic liver diseases are limited.However,recent studies have shown the contribution of cannabis smoking to the progression of liver fibrosis and steatosis.Moreover,controlling CB1 or CB2 signal-ling appears to be an attractive target in managing liver diseases.

Novel Method for Synthesis of Diarylpyrazole Derivatives as Cannabinoid CB_1 Receptor Antagonists

A novel and efficient method was developed for the synthesis of diarylpyrazole derivatives as cannabinoid CB1 receptor antagonist via four step reactions. The key step was the synthesis of a diarylpyrazole skeleton, which involved initial condensation of the sodium salt of compound 12 with diazonium compounds, and further cyclization by heating at reflux in acetic acid. Eight diarylpyrazole derivatives and nine new synthesized compounds were characterized by 1H NMR, IR, MS, and elemental analysis. The reaction conditions were mild and the overall yields of the target compounds ranged from 26% to 44%.

Local Peripheral Effects of <i>β</i>-Caryophyllene through CB₂Receptors in Neuropathic Pain in Mice

β-Caryophyllene (BCP) is known as a common constitute of the essential oils of numerous food plants and primary component in Cannabis. In this study, we investigated the effect of local intraplantar (i.pl.) injection of BCP on mechanical hypersensitivity induced by partial sciatic nerve ligation (PSNL) in mice. Relative to sham operation controls, mice with the PSNL displayed a maximum level of hyperresponsiveness to von Frey metallic filament on post-operative day 7. PSNL-induced allodynia was seen in the ipsilateral side of nerve ligation, but not in the contralateral side. The i.pl. injection of BCP into the ipsilateral hindpaw to PSNL attenuated mechanical allodynia in a dose-dependent manner. BCP injection into the contralateral hindpaw did not produce anti-allodynic effects, suggesting a local peripheral anti-allodynic effect of BCP. Anti-allodynic effects induced by i.pl. injection of BCP were prevented by pretreatment with the cannabinoid (CB2) receptor antagonist AM630, but not by the CB1 receptor antagonist AM251. These data suggest that i.pl. injection of BCP could produce anti-allodynia by activating peripheral CB2 receptors, but not CB1 receptors in a mouse model of neuropathic pain. Taken together, these results suggest that peripheral CB2 receptors may contribute to the effectiveness of BCP in the treatment of neuropathic pain disorders.

Pharmacological inhibition of cannabinoid receptor 1 stimulates gastric release of nesfatin-1 via the mTOR pathway

AIM To determine whether Nucb2/nesfatin1 production is regulated by the cannabinoid system through the intracellular m TOR pathway in the stomach.METHODS Sprague Dawley rats were treated with vehicle, rimonabant, rapamycin or rapamycin+rimonabant. Gastric tissue obtained from the animals was used for biochemical assays: Nucb2 m RNA measurement by real time PCR, gastric Nucb2/nesfatin protein content by western blot, and gastric explants to obtain gastric secretomes. Nucb2/nesfatin levels were measured in gastric secretomes and plasma using enzyme-linked immunosorbent assay. RESULTS The inhibition of cannabinoid receptor 1(CB1) by the peripheral injection of an inverse agonist, namely rimonabant, decreases food intake and increases the gastric secretion and circulating levels of Nucb2/nesfatin-1. In addition, rimonabant treatment activates m TOR pathway in the stomach as showed by the increase in pm TOR/m TOR expression in gastric tissue obtained from rimonabant treated animals. These effects were confirmed by the use of a CB1 antagonist, AM281. When the intracellular pathway m TOR/S6 k was inactivated by chronic treatment with rapamycin, rimonabant treatment was no longer able to stimulate the gastric secretion of Nucb2/nesfatin-1.CONCLUSION The peripheral cannabinoid system regulates food intake through a mechanism that implies gastric production and release of Nucb2/Nesfatin-1, which is mediated by the m TOR/S6 k pathway.

Pharmacological characterizationof synthetic cannabinoid MAM-2201：radioligand binding and abuse-related effects

OBJECTIVE Over 30% of all new psychoactive substances identified by the UN Office on Drugs and Crime in 2016 were synthetic cannabinoids.The recent emergence of MAM-2201 on the illicit market is troubling because this drug has no precedent in either the scientific or patent literature,and appears to be a novel compound developed specifically as a "graymarket" drug of abuse bystructurally combining the known synthetic cannabinoids JWH-122 and AM-2201.There is currently no published information regarding the pharmacology of MAM-2201.METHODS The present studies characterized cannabinoid-like effects of MAM-2201 in vitro(interactions with cannabinoid type 1 receptors[CB1 Rs]) and in vivo(in mice and rats).RESULTS In a radioligand binding assay using [3 H]CP55,940 in HEK cell membranes transfected with the CB1 R,MAM-2201(K i=5.4 nmol·L^(-1)),had higher binding affinity than WIN 55,212-2(K i=80 nmol·L^(-1)),and D9-THC(K i=8.3 nmol·L^(-1)).The E max values for MAM-2201 and WIN 55,212-2 in an assay of agonist inhibition of forskolin-stimulated c AMP were 85%(EC50=0.45 nmol·L^(-1)) and 95%,respectively,as compared with the D9-THC E max of 74%.In mice,MAM-2201(0.003-1.0 mg·kg^(-1),IP) produced dose-dependent cannabimimetic effects which were both more potent and more effective than those of D9-THC.MAM-2201 and D9-THC dose-dependently produced hypothermia:ED50=0.287 and 25.4 mg·kg^(-1),analgesia:ED50=0.125 and 29.4 mg·kg^(-1),and catalepsy:ED50=0.301 and18.9 mg·kg^(-1) in adult male CD1 mice.Importantly,MAM-2201 also elicited convulsant effects at a dose of 1.0 mg·kg^(-1) in 8/8 murine subjects.In rats,MAM-2201 produced dose-dependent D9-THC-like interoceptive effects in subjects trained to discriminate 3.0 mg·kg^(-1)(IP) D9-THC from saline.CONCLUSION MAM-2201 binds CB1 Rs with high affinity and agonist efficacy,and functions as a potent cannabinoid agonist in vivo across several complementary measures of cannabinoid activity in two rodent species.

Metabolic and inflammatory functions of cannabinoid receptor type 1 are differentially modulated by adiponectin

BACKGROUND Antagonists of cannabinoid type 1 receptor(CB1)have been shown to promote body weight loss and improve insulin sensitivity.Cannabinoids decrease adiponectin,and CB1 blocker increase adiponectin.However,the mediators of CB1 actions are not well defined.AIM To investigate whether the beneficial effects of CB1 inhibition are,at least in part,mediated by adiponectin.METHODS We compared metabolic and inflammatory phenotypes of wild-type(WT)mice,CB1-null(CB1^(-/-))and CB1/adiponectin double-knockout(DKO)mice.We assessed the insulin sensitivity using insulin tolerance test and glucose tolerance test,and inflammation using flow cytometry analysis of macrophages.RESULTS CB1^(-/-)mice exhibited significantly reduced body weight and fat mass when compared to WT mice.While no significance was found in total daily food intake and locomotor activity,CB1^(-/-)mice showed increased energy expenditure,enhanced thermogenesis in brown adipose tissue(BAT),and improved insulin sensitivity compared to WT mice.DKO showed no difference in body weight,adiposity,nor insulin sensitivity;only showed a modestly elevated thermogenesis in BAT compared to CB1^(-/-)mice.The metabolic phenotype of DKO is largely similar to CB1^(-/-)mice,suggesting that adiponectin is not a key mediator of the metabolic effects of CB1.Interestingly,CB1^(-/-)mice showed reduced pro-inflammatory macrophage polarization in both peritoneal macrophages and adipose tissue macrophages compared to WT mice;in contrast,DKO mice exhibited increased pro-inflammatory macrophage polarization in these macrophages compared to CB1^(-/-)mice,suggesting that adiponectin is an important mediator of the inflammatory effect of CB1.CONCLUSION Our findings reveal that CB1 functions through both adiponectin-dependent and adiponectin-independent mechanisms:CB1 regulates energy metabolism in an adiponectin-independent manner,and inflammation in an adiponectin-dependent manner.The differential effects of adiponectin on CB1-mediated metabolic and inflammatory functions should be taken into consideration in CB1 antagonist utilization.

Distribution and Possible Function of Cannabinoid Receptor Subtype 1 in the Human Prostate

Background: Cannabinoid receptor subtype 1 (CB1) has a relationship to the proliferation of various cells including malignant tumoral cells. We investigated and compared the expression of CB1 in benign and malignant human prostate tissues and in benign and malignant human prostate cell lines, as well as its function for the proliferation of human prostate cancer cells. Methods: Real-time quantitative PCR was performed to compare its expressions in human prostate tissues (normal, benign hyperplasia, and cancer) and prostate cell lines (3 normal and 3 malignant). For localization of CB1, immunofluorescent staining with rabbit anti-CB1 polyclonal antibodies and tetramethyl isothiocyanate (TRITC)-labeled swine anti-rabbit immunoglobulin (DAKO) were used under fluorescence microscope. To further analyze whether cell death was induced by anandamide (non-selective agonist for CB1/CB2) via a receptor dependent mechanism, the viability of DU145 cells, which is known as androgen-insensitive prostate cancer cell, was measured using MTT assay. Results: CB1mRNA was found to be expressed in the all 3 human prostate tissues, however, CB1 protein was expressed in BPH and low grade malignant PC tissues, but not in high grade malignant PC tissues. CB1 as for cell lines, the expression of CB1 was low in malignant cell lines except for DU145. Anandamide elicited cell death, which was significantly inhibited by AM251 (selective antagonist for CB1), indicating that cell death induced by anandamide in DU145 cells was mediated by CB1. Anandamide time-dependently elicits up-regulation of CB1 in DU145 cells. Conclusions: CB1 may be an inhibitory regulator of androgen-insensitive human prostate cancer epithelial cell growth.

Activation of cannabinoid receptor CB2 regulates LPS-induced pro-inflammatory cytokine production and osteoclastogenic gene expression in human periodontal ligament cells

Background and Objective: It has been found that human periodontal ligament (hPDL) cells express cannabinoid receptor CB2. However, the functional importance of CB2 in hPDL cells exposed to bacterial endotoxins is not known. Here we investigate if the inflammation promoter lipopolysaccharide (LPS) affects CB2 expression and if activation of CB2 regulates LPS-induced pro-inflammatory cytokine production and osteoclastogenic gene expression in hPDL cells. Methods: The hPDL cells were obtained from extracted teeth of periodontally healthy subjects. CB2 expression in hPDL cells exposed to LPS was deter- mined by quantitative real-time PCR analysis. Then, the cells were incubated with or without CB2-specific agonist HU-308 before further stimulation with LPS. In some experiments, the cells were pre-treated with CB2-specific antagonist SR144528. The production of pro-inflammatory cytokines interleukin-1 beta (IL- 1β), interleukin-6 (IL-6) and tumor necrosis factoralpha (TNF-α) was assessed by enzyme-linked immunosorbent assay (ELISA). The mRNA expression of osteoclastogenic genes osteoprotegerin (OPG) and receptor activator of NF-κB ligand (RANKL) was examined using quantitative real-time PCR analysis. Results: CB2 expression in hPDL cells was markedly enhanced by LPS. HU-308 significantly suppressed the production of IL-1β, IL-6 and TNF-α exposed to LPS, whereas SR144528 attenuated this effect. The OPG/RANKL ratio decreased when exposed to LPS, furthermore increased significantly with the addition of HU-308 and finally decreased markedly after pretreatment with SR144528. Conclusion: Our study demonstrated that activation of CB2 had anti-inflammatory and anti-resorptive effects on LPS-stimulated hPDL cells. These findings suggest that activation of CB2 might be an effective therapeutic strategy for the treatment of inflammation and alveolar bone resorption in periodontitis.

AB007. Expression and localization of CB1R,NAPE-PLD,and FAAH in the primary visual cortex of vervet monkeys

Background:The goal of this study is to determine the expression and localization of the cannabinoid receptor type 1(CB1R),the synthesizing enzyme N-acyl phosphatidyl-ethanolamine phospholipase D(NAPE-PLD),and the degradation enzyme fatty acid amide hydrolase(FAAH)in the vervet monkey area V1 to better understand the mechanisms underlying the effects of eCB system modulation on cortical visual processing.Methods:Using Western blots and immunohistochemistry,we investigated the laminar and cellular expression patterns of CB1R,NAPE-PLD,and FAAH across the rostrocaudal axis of the vervet monkey(Chlorocebus sabaeus)primary visual cortex.Results:CB1R,NAPE-PLD,and FAAH were expressed in V1 throughout the rostrocaudal axis.CB1R showed very low staining in layer(L)4,with higher expression in all other layers,especially L1,followed by L2 and L3.NAPE-PLD and FAAH expression patterns were similar,but not quite as low in L4.CB1R,NAPE-PLD,and FAAH were localized in vGlut2-positive cells,representing glutamatergic projection neurons,and in somatostatin(SST)-positive cells,a class of GABAergic interneurons.Conclusions:The low level of CB1R in L4 indicates less direct endocannabinoid modulation of V1 afferents from the dLGN,but that greater modulation may occur via the higher expression of CB1R in L2 and L3 on the way to the dorsal and ventral visual streams.This is further supported by the higher expression of NAPE-PLD and FAAH in these layers.Expression in vGlut2-positive and SST-positive cells represents a role at both glutamatergic and GABAergic neurons.These data indicate that CB1R may influence the network of activity patterns in the visual streams after the visual information has reached V1,and thus may influence visual perception.

AB059.Expression patterns of CB1R,NAPE-PLD,and FAAH in the primary visual cortex of vervet monkeys

Background:The expression,localization,and function of the endocannabinoid system has been well characterized in recent years in the monkey retina and in the primary thalamic relay,the lateral geniculate nucleus(dLGN).Few data are available on cortical recipients’structures of the dLGN,namely the primary visual cortex(V1).The goal of this study is to characterize the expression and localization of the metabotropic cannabinoid receptor type 1(CB1R),the synthesizing enzyme N-acyl phosphatidyl-ethanolamine phospholipase D(NAPE-PLD),and the degradation enzyme fatty acid amide hydrolase(FAAH)in the vervet monkey area V1.Methods:Using Western blots and immunohistochemistry,we investigated the expression patterns of CB1R,NAPE-PLD,and FAAH in the vervet monkey primary visual cortex.Results:CB1R,NAPE-PLD,and FAAH were expressed in the primary visual cortex throughout the rostro-caudal axis.CB1R showed very low levels of staining in cortical layer 4,with higher expressions in all other cortical layers,especially layer 1.NAPE-PLD and FAAH expressions were highest in layers 1,2 and 3,and lowest in layer 4.Conclusions:Interestingly enough,CB1R was very low in layer 4 of V1 in comparison to the other cortical layers.The visual information coming from the dLGN and entering layer 4Calpha(magno cells)and 4Cbeta(parvo cells)may be therefore modulated by the higher expression levels of CB1R in cortical layers 2 and 3 on the way to the dorsal and ventral visual streams.This is further supported by the higher expression of NAPE-PLD and FAAH in the outer cortical layers.These data indicate that CB1R system can influence the network of activity patterns in the visual stream after the visual information has reached area V1.These novel results provide insights for understanding the role of the endocannabinoids in the modulation of cortical visual inputs,and hence,visual perception.

Activation of Cannabinoid Receptor 1 in GABAergic Neurons in the Rostral Anterior Insular Cortex Contributes to the Analgesia Following Common Peroneal Nerve Ligation

The rostral agranular insular cortex(RAIC)has been associated with pain modulation.Although the endogenous cannabinoid system(eCB)has been shown to regulate chronic pain,the roles of eCBs in the RAIC remain elusive under the neuropathic pain state.Neuropathic pain was induced in C57BL/6 mice by common peroneal nerve(CPN)ligation.The roles of the eCB were tested in the RAIC of ligated CPN C57BL/6J mice,glutamatergic,or GABAergic neuron cannabinoid receptor 1(CB1R)knockdown mice with the whole-cell patch-clamp and pain behavioral methods.The E/I ratio(amplitude ratio between mEPSCs and mIPSCs)was significantly increased in layer V pyramidal neurons of the RAIC in CPN-ligated mice.Depolarization-induced suppression of inhibition but not depolarization-induced suppression of excitation in RAIC layer V pyramidal neurons were significantly increased in CPN-ligated mice.The analgesic effect of ACEA(a CB1R agonist)was alleviated along with bilateral dorsolateral funiculus lesions,with the administration of AM251(a CB1R antagonist),and in CB1R knockdown mice in GABAergic neurons,but not glutamatergic neurons of the RAIC.Our results suggest that CB1R activation reinforces the function of the descending pain inhibitory pathway via reducing the inhibition of glutamatergic layer V neurons by GABAergic neurons in the RAIC to induce an analgesic effect in neuropathic pain.

CB1R拮抗剂对MPTP诱导PD小鼠运动行为影响

目的研究大麻素受体1(CB1R)拮抗剂NESS 0327对1-甲基-4-苯基-1,2,3,6-四氢吡啶(MPTP)诱导的帕金森病(PD)小鼠运动行为的影响。方法将24只8周龄C57BL/6J雄性小鼠随机分为对照组、MPTP组和MPTP+NESS 0327组。对照组和MPTP组小鼠均双侧黑质致密部(SNpc)微量注射二甲基亚砜(DMSO)和Tween-80混合溶液,分别腹腔注射生理盐水和MPTP;MPTP+NESS 0327组小鼠则双侧SNpc微量注射NESS 0327,腹腔注射MPTP。小鼠连续5 d给药后进行旷场实验和爬杆实验检测小鼠运动能力的改变。结果旷场实验结果显示,3组小鼠总移动距离比较差异具有统计学意义(F=8.279,P<0.01),其中MPTP组小鼠总移动距离较对照组小鼠显著减少(q=5.705,P<0.01),MPTP+NESS 0327组小鼠总移动距离较MPTP组小鼠显著增加(q=3.504,P<0.05)。爬杆实验结果显示,3组小鼠下杆时间比较差异具有统计学意义(F=12.110,P<0.01),其中MPTP组小鼠下杆时间较对照组小鼠显著增加(q=6.790,P<0.01),MPTP+NESS 0327组小鼠的下杆时间较MPTP组小鼠显著减少(q=4.713,P<0.01)。结论SNpc给予CB1R拮抗剂NESS 0327可改善MPTP诱导的PD小鼠运动功能障碍。

大麻素1型受体参与疼痛调节机制的研究进展

大麻素1型受体(CB1R)是近年来研究较为广泛的内源性大麻素受体之一,在中枢和外周神经系统均有表达。CB1R位于突触前膜,通过逆行抑制性突触传递调节神经递质的释放,是治疗疼痛的有效靶点。激活CB1R对伤害性、病理性和炎性疼痛均具有镇痛效应,拮抗CB1R可引起疼痛敏化。本文通过对CB1R结构功能、信号转导、镇痛机制方面进行综述,为进一步了解疼痛的病理生理学机制及探索更优疼痛治疗方法提供参考。

Dopaminergic system does not play a major role in the precipitated cannabinoid withdrawal syndrome

AIM:To determine the dopaminergic system involvement in precipitated cannabinoid withdrawal syndrome.METHODS:The dopamine D_(1)receptor antagonist SCH23390 or the dopamine D_(2)receptor antagonist sulphide was administered to rats chronically treated with either△^(9)-tetrahydrocannabinol(THC)or vehicle.Subjects were then injected with either SR141716A or vehicle and behavior was observed for 1 h.RESULTS:Administration of the cannabinoid receptor antagonist SR141716A to animals chronically treated with THC as described by Tsou et al(1995)produced a profound withdrawal syndrome.Treatment with dopamine antagonists did not attenuate cannabinoid precipitated withdrawal syndrome in THC tolerant animals while the agonists increased the syndrome.CONCLUSION:It is unlikely that the dopaminergic system plays a major role in mediating the behavioral aspects of the cannabinoid withdrawal syndrome.