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.

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.

Central CB2 receptors in inflammation-driven neurodegeneration： dysregulation and therapeutic potential

In recent times there has been an intensification of interest in the pathological role of neuroinflammation in neurodegenerative disease. Neuroprotective strategies to slow, halt or reverse neuro- degeneration have not proven fruitful clinically, and the notion of a multi-hit hypothesis in the progression of neurodegenerative disease has steered focus towards other contributory pathological factors, particularly neuroinflammation. Neuroinflammation is believed to sustain the neurodegenerative pathology, forming a cy- clical and self-sustaining pathological process, with dying neurons activating microglia, which, once activated, can release several fac- tors that kill further neurons （reviewed in Blandini, 2013）.

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.

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.

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.

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%.

EVs-mediated delivery of CB2 receptor agonist for Alzheimer’s disease therapy

Alzheimer’s disease(AD)is a typical neurodegenerative disease that leads to irreversible neuronal degeneration,and effective treatment remains elusive due to the unclear mechanism.We utilized biocompatible mesenchymal stem cell-derived extracellular vesicles as carriers loaded with the CB2 target medicine AM1241(EVs-AM1241)to protect against neurodegenerative progression and neuronal function in AD model mice.According to the results,EVs-AM1241 were successfully constructed and exhibited better bioavailability and therapeutic effects than bare AM1241.The Morris water maze(MWM)and fear conditioning tests revealed that the learning and memory of EVs-AM1241-treated model mice were significantly improved.In vivo electrophysiological recording of CA1 neurons indicated enhanced response to an auditory conditioned stimulus following fear learning.Immunostaining and Western blot analysis showed that amyloid plaque deposition and amyloidβ(Aβ)-induced neuronal apoptosis were significantly suppressed by EVs-AM1241.Moreover,EVs-AM1241 increased the number of neurons and restored the neuronal cytoskeleton,indicating that they enhanced neuronal regeneration.RNA sequencing revealed that EVs-AM1241 facilitated Aβphagocytosis,promoted neurogenesis and ultimately improved learning and memory through the calcium-Erk signaling pathway.Our study showed that EVs-AM1241 efficiently reversed neurodegenerative pathology and enhanced neurogenesis in modelmice,indicating that they are very promising particles for treating AD.

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.

CB_1 Cannabinoid Receptor-Dependent and-Independent Inhibition of Depolarization-Induced Calcium Influx in Oligodendrocytes

Ca2+稳态平衡的调节在少突胶质细胞功能和存活中起重要作用。大麻素CB1和CB2受体在许多细胞中调节Ca2+水平和/或K+电流。本文利用培养的少突胶质细胞中,通过增高细胞外K+浓度(50 mM诱导膜去极化,研究大麻素复合物在此过程引发钙内流中的作用。CB2受体激动剂ACEA导致去极化诱导的少突胶质细胞胞浆的Ca2+瞬变表达浓度依赖性抑制,最大效应为(94±3)%,半效应浓度(EC50)为(1.3±0.03)μM。这种作用可被CB2/CB2激动剂CP55、940、内源性大麻素类AEA和2-AG所模拟,但是CB2受体选择性激动剂J WH133没有作用。CB2受体拮抗剂AM251(1μM)也可减少细胞外高K+诱导的Ca2+反应,但不能防止ACEA(3μM)诱发的抑制效应。然而,ACEA和AEA减少去极化诱导的Ca2+瞬变的能力在CB2受体敲除小鼠和经百日咳毒素预处理的少突胶质细胞中明显降低。内流性K+通道阻断剂BaCl2(300μM)和CsCl2(1 mM)降低电压诱导的Ca2+内流并部分阻断ACEA的抑制效应。本文表明,大麻素抑制少突胶质细胞中去极化诱导的Ca2+瞬变是通过包括PTX-敏感的Gi/o蛋白和阻断K+内流通道的CB2受体依赖性和非依赖性机制。

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.

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.

Endocannabinoid 2-arachidonoylglycerol protects inflammatory insults from sulfur dioxide inhalation via cannabinoid receptors in the brain

Sulfur dioxide（SO_2） pollution in the atmospheric environment causes brain inflammatory insult and inflammatory-related microvasculature dysfunction.However,there are currently no effective medications targeting the harmful outcomes from chemical inhalation.Endocannabinoids（eCBs） are involved in neuronal protection against inflammation-induced neuronal injury.The 2-arachidonoylglycerol（2-AG）,the most abundant eCBs and a full agonist for cannabinoid receptors（CB1 and CB2）,is also capable of suppressing proinflammatory stimuli and improving microvasculature dysfunction.Here,we indicated that endogenous 2-AG protected against neuroinflammation in response to SO_2 inhalation by inhibiting the activation of microglia and astrocytes and attenuating the overexpression of inflammatory cytokines,including tumor necrosis factor alpha（TNF-a）,interleukin（IL）-1β,and inducible nitric oxide synthase（iNOS）.In addition,endogenous 2-AG prevented cerebral vasculature dysfunction following SO_2 inhalation by inhibiting endothelin 1（ET-1）,vascular cell adhesion molecule-1（VCAM-1） and intercellular adhesion molecule 1（ICAM-1） expression,elevating endothelial nitric oxide synthase（eNOS） level,and restoring the imbalance between thromboxane A2（TXA2） and prostaglandin 12（PGI2）.In addition,the action of endogenous 2-AG on the suppression of inflammatory insult and inflammatory-related microvasculature dysfunction appeared to be mainly mediated by CB1 and CB2 receptors.Our results provided a mechanistic basis for the development of new therapeutic approaches for protecting brain injuries from SO_2 inhalation.

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.

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.

Effects of cannabinoid receptor type 2 on endogenous myocardial regeneration by activating cardiac progenitor cells in mouse infarcted heart

Cannabinoid receptor type 2(CB2)activation is recently reported to promote proliferation of some types of resident stem cells(e.g.,hematopoietic stem/progenitor cell or neural progenitor cell).Resident cardiac progenitor cell(CPC)activation and proliferation are crucial for endogenous cardiac regeneration and cardiac repair after myocardial infarction(MI).This study aims to explore the role and possible mechanisms of CB2receptor activation in enhancing myocardial repair.Our results revealed that CB2receptor agonist AM1241 can significantly increase CPCs by c-kit and Runx1 staining in ischemic myocardium as well as improve cardiomyocyte proliferation.AM1241 also decreased serum levels of MDA,TNF-αand IL-6 after MI.In addition,AM1241 can ameliorate left ventricular ejection fraction and fractional shortening,and reduce fibrosis.Moreover,AM1241 treatment markedly increased p-Akt and HO-1 expression,and promoted Nrf-2 nuclear translocation.However,PI3K inhibitor wortmannin eliminated these cardioprotective roles of AM1241.In conclusion,AM1241 could induce myocardial regeneration and improve cardiac function,which might be associated with PI3K/Akt/Nrf2 signaling pathway activation.Our findings may provide a promising strategy for cardiac endogenous regeneration after MI.

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.

Cannabinoid receptor-2 selective antagonist negatively regulates receptor activator of nuclear factor kappa B ligand mediated osteoclastogenesis

Background The cannabinoid receptor-2 （CB2） is important for bone remodeling. In this study, we investigated the effects of CB2 selective antagonist （AM630） on receptor activator of nuclear factor kappa B （RANK） ligand （RANKL）induced osteoclast differentiation and the underlying signaling pathway using a monocyte-macrophage cell line-RAW264.7.Methods RAW264.7 was cultured with RANKL for 6 days and then treated with AM630 for 24 hours. Mature osteoclasts were measured by tartrate-resistant acid phosphatase （TRAP） staining using a commercial kit. Total ribonucleic acid （RNA）was isolated and real-time reverse transcriptase-polymerase chain reaction （RT-PCR） was done to examine the expression of RANK, cathepsin K （CPK） and nuclear factor kappa B （NF-κB）. The extracellular signal-regulated kinase （ERK）,phosphorylation of ERK （P-ERK） and NF-κB production were tested by Western blotting. The effect of AM630 on RAW264.7 viability was determined using the 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazoliumbromide （MTT） assay.Results AM630 did not affect the viability of RAW264.7. However, this CB2 selective antagonist markedly inhibited osteoclast formation and the inhibition rate was dose-dependent. The dose of 〉100 nmol/L could reduce TRAP positive cells to the levels that were significantly lower than the control. AM630 suppressed the expression of genes associated with osteoclast differentiation and activation, such as RANK and CPK. An analysis of a signaling pathway showed that AM630 inhibited the RANKL-induced activation of ERK, but not NF-κB.Conclusion AM630 could inhibit the osteoclastogenesis from RAW264.7 induced with RANKL.

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.

电针对佐剂性关节炎大鼠病灶局部皮肤CB2受体阳性细胞免疫反应性的影响

目的:研究电针缓解炎性痛的机制是否与其对病灶局部内源性大麻素2型受体(CB2受体)阳性细胞免疫反应性的影响有关。方法:采用健康成年雌性SD大鼠共48只,随机分为:空白对照组(n=12)、模型组(n=12)、穴位电针组(n=12)和非穴位电针对照组(n=12)。除空白对照组外其它各组大鼠于左后肢外踝关节皮下注射完全弗式佐剂(CFA,Sigma公司产品)50μL制备单发局限性佐剂性关节炎模型。对其进行行为学观察,研究电针患侧“环跳”穴、“阳陵泉”穴对背屈、跖屈踝关节疼痛试验评分的影响,并结合免疫组化技术,观察电针对佐剂性关节炎大鼠致炎后第6天和第16天病灶局部皮肤CB2受体阳性细胞免疫反应性的影响。结果:①电针佐剂性关节炎模型大鼠致炎足同侧穴位,可产生明显镇痛作用,且电针效果在致炎后第3-5天最为显著,穴位电针组背屈、跖屈踝关节疼痛试验评分在致炎第3天和5天均较模型组和非穴位电针对照组显著降低(P<0.05)。②免疫组化结果显示,致炎后第6天穴位电针组大鼠炎性痛病灶局部皮肤组织CB2受体阳性细胞的数量显著高于空白对照组、模型组和非穴位电针组(P<0.05);致炎后第16天穴位电针组该值与空白对照组、模型组和非穴位电针组间统计学差异不明显(P>0.05)。结论:电针腧穴可使炎症病灶局部皮肤组织CB2受体免疫反应阳性细胞的数量显著上调,从而调控炎性痛病灶局部组织中致炎致痛物质与镇痛物质之间的平衡,解除局部病灶神经免疫微环路的激活状态,通过外周途径缓解疼痛。