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.

利莫那班对颅脑外伤模型大鼠癫痫易感性的影响

目的:观察利莫那班在大鼠颅脑外伤后不同时期对癫痫易感性的影响,探讨利莫那班能否干预外伤后癫痫的发生。方法:105只大鼠分为模型处理组(45只)、模型组(45只)和空白对照组(15只)。模型处理组和模型组大鼠通过外侧液压打击法制备颅脑外伤模型,并在打击后2min分别腹腔注射利莫那班和生理盐水。上述2组大鼠继续均分为3个不同时间点(每个时间点15只),分别在液压打击后24h、1周和6周时腹腔注射戊四唑,空白对照组大鼠直接腹腔注射戊四唑。观察各组大鼠癫痫发生的潜伏期和出现全身强直阵挛性癫痫(GTCS)大鼠的数量。结果:液压打击后6周时,模型组大鼠癫痫发生的潜伏期较打击后24h时和1周时缩短(F=12.93,P=0.023;F=11.80,P=0.016);模型处理组大鼠癫痫发生的潜伏期在打击后24h时较液压打击后1周时和6周时缩短(F=22.51,P=0.001;F=11.69,P=0.024)。空白对照组大鼠癫痫发生的潜伏期较模型组6周时(F=14.74,P=0.03)和模型处理组24h时(F=18.33,P=0.007)延长;打击后24h时,模型组大鼠癫痫发生的潜伏期较模型处理组延长(t=2.97,P=0.009);打击后6周时,模型组大鼠癫痫发生的潜伏期较模型处理组缩短(t=2.31,P=0.033)。在打击后6周时模型处理组发生GTCS大鼠的数量较模型组减少(χ2=6.67,P=0.033)。结论:利莫那班在脑外伤后急性期时可增加癫痫易感性,而在慢性期时其可降低癫痫易感性。

利莫那班对肝纤维化C57小鼠肝组织大麻素受体1及α-SMA表达的影响

目的研究大麻素受体1(CB1)拮抗剂利莫那班对肝纤维化模型C57小鼠肝组织中CB1、α-平滑肌肌动蛋白(α-SMA)表达的影响,及其抗肝纤维化的作用机制。方法 30只C57小鼠随机分为3组,分别为正常对照组、模型对照组及利莫那班组,每组10只。采用四氯化碳腹腔注射诱导形成小鼠肝纤维化模型。造模2周后于继续造模同时,正常对照组和模型对照组每天生理盐水灌胃,利莫那班组用利莫那班灌胃。第8周造模结束时处死小鼠,留取肝脏组织标本,分别进行HE和Masson三色染色,应用免疫组织化学方法检测肝组织中CB1和α-SMA的表达,并进行肝组织纤维化评分(S评分)。结果模型对照组和利莫那班组肝组织S评分、CB1和α-SMA阳性表达量均高于正常对照组(均P<0.05),利莫那班组均低于模型对照组(均P<0.05);正常对照组、模型对照组和利莫那班组CB1评分、α-SMA评分与S评分相互之间均呈正相关(均P<0.05)。结论肝组织CB1的激活可促进肝纤维化的形成,CB1拮抗剂利莫那班通过抑制CB1表达,进而抑制肝星状细胞的增殖和激活,从而起到抗肝纤维化的作用。

脊髓背角CB_1受体参与CP55940对病理性神经痛大鼠的镇痛作用

目的观察脊髓背角大麻素受体1（cannabinoid receptor 1,CB1R）在大麻素类药物CP55940对慢性坐骨神经结扎（chronic constriction injury,CCI）所致的神经病理性疼痛大鼠镇痛效应中的作用,并初步探讨其机制。方法 8周龄雄性SD大鼠56只分为7组：1假手术组,2CCI组（鞘内注射DMSO生理盐水）,3AM251＋CCI组（鞘内注射10^-8mol/L AM251）,4～6CP55940（0.01、0.05、0.20 mg/kg）＋CCI组（鞘内注射0.01、0.05、0.20 mg/kg CP55940）,7AM251＋CP55940＋CCI组（预先鞘内注射10^-8mol/L AM251,10 min后给予0.05 mg/kg CP55940）;每组8只。假手术组大鼠不进行鞘内置管,仅游离坐骨神经不结扎;其余各组大鼠在鞘内置管5 d后行CCI术,术后分别鞘内给予各种药物。分别在CCI术前1 d,术后1、3、5、7、10、14 d鞘内给药1 h后测定热缩足潜伏期（thermal withdrawal latency,TWL）;术后第7、14 d处死大鼠,取术侧L4～L6脊髓背角,采用免疫印迹技术检测脊髓背角CB1R及蛋白激酶A（protein kinase A,PKA）表达的变化。结果大鼠CCI术后即形成稳定的热痛敏,TWL明显缩短;与CCI组相比,鞘内给予非选择性CB受体激动剂CP55940 0.05 mg/kg可明显延长CCI大鼠TWL（P〈0.05）;选择性CB1R拮抗剂AM251（10^-8mol/L）可部分阻断CP55940的镇痛效果（P〈0.05）。免疫印迹实验结果显示,与假手术组相比,CCI组大鼠在术后7、14 d术侧脊髓背角CB1R、PKA表达明显增加（P〈0.05）;鞘内给予CP55940可显著降低CCI大鼠的PKA表达（P〈0.05）;CB1R拮抗剂AM251显著降低了CCI大鼠的CB1R表达（P〈0.05）,同时阻断了CP55940降低CCI大鼠PKA表达的效应（P〈0.05）。结论鞘内注射大麻素类药物CP55940对CCI所致的神经痛具有良好的镇痛效应,CB1受体可能通过抑制PKA的活性参与了CP55940的镇痛作用。

CB1受体参与运动疲劳损害小鼠皮层-纹状体通路eCB-LTD的调节

目的:通过研究小鼠运动疲劳后皮层-纹状体通路内源性大麻素介导的长时程抑制(endocannabinoid-mediated long-term depression,e CB-LTD)的变化,揭示运动疲劳对小鼠皮层-纹状体通路突触可塑性的影响。方法:C57/BL6雄性成年小鼠,随机分为对照组(Control)和运动疲劳组(exercise-induced fatigue,EF)。利用电动跑台建立重复力竭的运动疲劳小鼠模型。采用离体脑片场电位记录技术,检测小鼠皮层-纹状体通路的LTD,并通过加入大麻素1型(cannabinoid 1,CB1)受体的拮抗剂AM251,鉴定该LTD是否依赖于内源性大麻素系统(endocannabinoid system,ECS);采用离体脑片全细胞膜片钳技术,检测小鼠纹状体中型棘状神经元(medium spiny neurons,MSNs)的基本电生理特性;采用免疫印迹技术,检测小鼠纹状体脑区CB1受体的蛋白表达含量。结果:1)与对照组相比,运动疲劳组小鼠皮层-纹状体通路的LTD显著受损(P<0.01),且该LTD能够被CB1受体拮抗剂AM251阻断,证实其为eCBLTD。2)运动疲劳组小鼠纹状体MSNs的基本电生理特性与对照组小鼠相比无差异(P>0.05)。3)与对照组相比,运动疲劳组小鼠纹状体脑区CB1受体的表达含量显著上调(P<0.01)。结论:小鼠运动疲劳后皮层-纹状体通路的eCB-LTD受损,但是纹状体MSNs的基本电生理特性不变,CB1受体蛋白表达含量升高可能是对eCB-LTD受损的一种代偿反应。我们的实验结果第一次证实运动疲劳损害小鼠皮层-纹状体通路的eCB-LTD,提示皮层-纹状体通路突触可塑性异常可能是运动疲劳发生或维持的机制之一。

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.

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.

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%.

Endocannabinoid system: A newer molecular target for the treatment of alcohol-related behaviors

The cannabinoid （CB） receptors, endocannabinoids （eCB） and their synthesizing and catabolizing enzymes and the proteins involved in their transport, constitute what is now recognized as the eCB system. The eCBs are a class of lipids that have been identifed as retro-grade messengers and produce their effects via presyn-aptic CB receptors. The major function of the eCBs has been suggested to be that of modulating the release of several neurotransmitters implicated in a number of biological functions that include reward and reinforce-ment. There is now significant evidence to suggest that the eCB system plays an important role in the development of alcohol tolerance, dependence and relapse. Recent studies suggest that the pharmacological manipulation of the eCB system has the potential not only to block the direct reinforcing properties of alcohol but also alleviate behavioral abnormalities associated with relapse. There is also accumulating evidence that points to the possible utility of the eCB system targeted drugs in the treatment of alcoholism-related behavioral disorders. The agents that block CB1 receptor function or inhibit the synthesis of eCBs are attractive candidate drugs that need to be explored. Further understanding of the role of the eCB system in molecular mechanism/s that underlies alcoholism-related behaviors should lead to a better treatment of this devastating disorder.

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.

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.

The endocannabinoid system:A new pharmacological target for obesity treatment?

Being a great threaten for human health, obesity has become a pandemic chronic disease. There have been several therapeutic treatments for this social health issue, including diet and exercise therapy, medication and surgery, among which the diet is still the most common way. However, none of these therapeutic measures available is ideal, making it necessary to find an effective medical treatment. The endocannabinoid system, which is well known for its contributions in certain mental processes such as relaxation, amelioration of pain and anxiety, and sedation initiation, has been recently reported to play an essential role in regulating appetite and metabolism to maintain energy balance, leading to the belief that endocannabinoid system is closely related to obesity. This new discovery deepens our understanding of obesity, and provides us with a new direction for clinical obesity treatment. Rimonabant is an antagonist for CB1, and has entered the market in some countries. However, although effective as an anti-obesity drug, rimonabant also causes obviously adverse side-effects, thus is being doubted and denied for medical usage.

CB 1 cannabinoid receptor participates in the vascular hyporeactivity resulting from hemorrhagic shock in rats

Background Vascular hyporeactivity, which occurs in the terminal stage of hemorrhagic shock, is believed to be critical for treating hemorrhagic shock. The present study was designed to examine whether the CB1 cannabinoid receptor （CB1 R） was involved in the development of vascular hyporeactivity in rats suffering from hemorrhagic shock. Methods Sixteen animals were randomly divided into two groups （n=8 in each group）： sham-operated （Sham） and hemorrhagic shock （HS） groups. Hemorrhagic shock was induced by bleeding. The mean arterial pressure （MAP） was reduced to and stabilized at （25±5） mmHg for 2 hours. The vascular reactivity was determined by the response of MAP to norepinephrine （NE）. In later experiments another twelve animals were used in which the changes of CB1R mRNA and protein in aorta and superior mesenteric artery （SMA） were analyzed by RT-PCR and Western blotting. In addition, we investigated the effects of a CB1R antagonist on the vascular hyporeactivity and survival rates in rats with hemorrhagic shock. Survival rates were analyzed by the Fisher＇s exact probability test. The MAP response was analyzed by one-way analysis of variance （ANOVA）. Results Vascular hyporeactivity developed in all animals suffering from hemorrhagic shock. The expression of CBIR mRNA and protein in aorta and 2-3 branches of the SMA were significantly increased in the HS group after the development of vascular hyporeactivity when compared to those in Sham group. When SR141716A or AM251 was administered, the MAP response to NE was （41.75±4.08） mmHg or （44.78±1.80） mmHg respectively, which was higher than that in saline groups with （4.31±0.36） mmHg （P 〈0.01）. We also showed an increased 4-hour survival rate in the SR141716A or AM251-treated group with 20% or 30%, but with a statistically significant difference present between the AM251-treated and saline groups （P 〈0.05）. Conclusions CBIR is involved in vascular hyporeactivity resulting from hemorrhagic shock in rats, and CB1R antagonist may be useful in treating patients with traumatic, hemorrhagic shock who need field-rescue or initial treatment.