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.
Rats ; Animals ; Rimonabant/pharmacology* ; Memory ; Sleep, REM ; Receptors, Cannabinoid ; Cannabinoids/pharmacology*

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.
Mice ; Animals ; Insular Cortex ; Peroneal Nerve ; Mice, Inbred C57BL ; Neuralgia ; GABAergic Neurons ; Analgesia ; Analgesics ; Receptors, Cannabinoid

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.
Animals ; Callithrix ; Receptors, Cannabinoid ; Anxiety ; Amygdala ; Cannabinoids ; Phenotype

Excessive and persistent inflammatory responses are a potential pathological condition that can lead to diseases of various systems, including nervous, respiratory, digestive, circulatory, and endocrine systems. Cannabinoid type 2 receptor(CB2R) belongs to the G protein-coupled receptor family and is widely distributed in immune cells, peripheral tissues, and the central nervous system. It plays a role in inflammatory responses under various pathological conditions. The down-regulation of CB2R activity is an important marker of inflammation and and CB2R modulators have been shown to have anti-inflammatory effects. This study explored the relationship between CB2R and inflammatory responses, delved into its regulatory mechanisms in inflammatory diseases, and summarized the research progress on CB2R modulators from plants other than cannabis, including plant extracts and monomeric compounds, in exerting anti-inflammatory effects. The aim is to provide new insights into the prevention and treatment of inflammatory diseases.
Cannabinoid Receptor Modulators/pharmacology* ; Cannabinoid Receptor Agonists/pharmacology* ; Receptors, Cannabinoid ; Cannabinoids/pharmacology* ; Anti-Inflammatory Agents/pharmacology*

OBJECTIVE: To investigate the protective effect of cannabinoid receptor 2 (CB2) activation against acute lung injury in rats with lipopolysaccharide (LPS)-induced sepsis and explore the underlying mechanism. METHODS: Forty-eight SD rats were randomly assigned into control group, model group, CB2 agonist group and P38 MAPK inhibitor group (n=12). In the latter 3 groups, the rats received intraperitoneal injection of LPS to induce sepsis, and the control rats were given saline injection. In CB2 agonist group, JWH133 (3 mg/kg) was injected intraperitoneally 30 min before LPS injection; in P38 MAPK inhibitor group, the rats received intraperitoneal injection of SB203580 (5 mg/kg) 30 min prior to JWH133 injection. The changes in lung histopathology, water content, fluid clearance rate, inflammatory factors, pulmonary expressions of CB2 and tight junctionrelated genes, and phosphorylation of P38 MAPK in the lung tissues were examined. RESULTS: The rat models of sepsis showed severe damage of alveolar structures with significantly decreased fluid clearance rate, lowered pulmonary expressions of CB2, occludin and ZO-1 mRNA and proteins, increased water content in the lung tissue, and increased phosphorylation level of P38 MAPK and TNF-α and IL-1β levels in lung lavage fluid (all P < 0.05). Treatment with JWH133 improved alveolar pathology in the septic rats, but there was still inflammatory infiltration; lung tissue water content, phosphorylation of P38 MAPK, and TNF-α and IL-1β levels in lung lavage fluid were all significantly decreased, and the fluid clearance rate, pulmonary expressions of CB2, occludin and ZO-1 were significantly increased (all P < 0.05). Additional treatment with SB203580 resulted in further improvements of alveolar pathologies, lowered phosphorylation levels of P38 MAPK in the lung tissue and TNF-α and IL-1β levels in lung lavage fluid, and increased the protein expressions of occludin and ZO-1 (P < 0.05) without causing significant changes in mRNA and protein expression of CB2 (P > 0.05). CONCLUSION In rats with LPS-induced sepsis, activation of CB2 can inhibit the p38 MAPK signaling pathway, reduce the release of inflammatory factors in the lung tissues, promote tight junction protein expressions, and thus offer protection against acute lung injury.
Acute Lung Injury/metabolism* ; Animals ; Cannabinoids ; Lipopolysaccharides/adverse effects* ; Lung/pathology* ; Occludin/metabolism* ; RNA, Messenger/metabolism* ; Rats ; Rats, Sprague-Dawley ; Receptor, Cannabinoid, CB2 ; Receptors, Cannabinoid/metabolism* ; Sepsis/metabolism* ; Tumor Necrosis Factor-alpha/metabolism* ; Water/metabolism* ; p38 Mitogen-Activated Protein Kinases/metabolism*

Phytocannabinoids are bioactive terpenoids that are exclusive to Cannabis sativa L. The main pharmacologically active phytocannabinoids are Δ9-tetrahydrocannabinol and cannabidiol, both target endogenous cannabinoid receptors. Δ9-tetrahydrocannabinol and cannabidiol have extensive therapeutic potential due to their participation in many physiological and pathological processes in human body by activating the endocannabinoid system. At present, Δ9-tetrahydrocannabinol, cannabidiol and their analogues or combination preparations are used to treat epilepsy, vomiting in patients with cancer chemotherapy, spasticity in multiple sclerosis and relieve neuropathic pain and pain in patients with advanced cancer. With the further exploration of the application value of Δ9-tetrahydrocannabinol and cannabidiol as well as the increasing demand for standardization of pharmaceutical preparations, it is imminent to achieve large-scale production of Δ9-tetrahydrocannabinol and cannabidiol in the pharmaceutical industry. In this article, pharmacological research progress of phytocannabinoids in recent years, biosynthetic pathways of phytocannabinoids and the mechanism of key enzymes as well as various product development strategies of cannabinoids in pharmaceutical industry are reviewed. By exploring the potential of synthetic biology as an alternative strategy for the source of phytocannabinoids, it will provide a theoretical basis for the research and development of microbial engineering for cannabinoids synthesis, and promote the large-scale production of medicinal cannabinoids.
Cannabidiol ; Cannabinoids/biosynthesis* ; Cannabis ; Humans ; Receptors, Cannabinoid

Cannabinoid receptor type 2( CB2 R),a member of the G protein-coupled receptor( GPCR) superfamily,has a variety of biological activities,such as regulating pain response,resisting inflammation and fibrosis,and mediating bone metabolism. Some CB2 R regulators exhibit a good regulatory effect on bone metabolism. Cannabinoids in Cannabis sativa can cause psychoactive effects despite various pharmacological actions they exerted by targeting CB2 R. Therefore,it is of great significance to discover CB2 R regulators in non-Cannabis plants for finding new lead compounds without psychoactive effects and elucidating the action mechanism of plant drugs. The present study clarifies the discovery,structure,and physiological functions of CB2 R,especially its regulatory effects on bone metabolism,summarized CB2 R regulators extracted from non-Cannabis plants,and systematically analyzes the regulatory effects of CB2 R regulators on bone metabolism in animals,osteoblasts,and osteoclasts,to provide a scientific basis for the discovery of new CB2 R regulators and the development of anti-osteoporotic drugs.
Animals ; Cannabinoids/pharmacology* ; Cannabis ; Osteoblasts ; Osteoclasts ; Receptors, Cannabinoid

Cardiovascular Diseases ; Humans ; Receptors, Cannabinoid

Objective To investigate the expression of cannabinoid type 2 receptor （CB2R） at different time points after brain contusion and its relationship with wound age of mice. Methods A mouse brain contusion model was established with PCI3000 Precision Cortical Impactor. Expression changes of CB2R around the injured area were detected with immunohistochemical staining, immunofluorescent staining and Western blotting at different time points. Results Immunohistochemical staining results showed that only a few cells in the cerebral cortex of the sham operated group had CB2R positive expression. The ratio of CB2R positive cells gradually increased after injury and reached the peak twice at 12 h and 7 d post-injury, followed by a decrease to the normal level 28 d post-injury. The results of Western blotting were consistent with the immunohistochemical staining results. Immunofluorescent staining demonstrated that the changes of the ratio of CB2R positive cells in neurons, CB2R positive cells in monocytes and CB2R positive cells in astrocytes to the total cell number showed a single peak pattern, which peaked at 12 h, 1 d and 7 d post-injury, respectively. Conclusion The expression of CB2R after brain contusion in neurons, monocytes and astrocytes in mice suggests that it is likely to be involved in the regulation of the biological functions of those cells. The changes in CB2R are time-dependent, which suggests its potential applicability as a biological indicator for wound age estimation of brain contusion in forensic practice.
Animals ; Blotting, Western ; Brain Contusion/metabolism* ; Brain Injuries ; Forensic Pathology ; Mice ; Muscle, Skeletal/pathology* ; Receptor, Cannabinoid, CB2/metabolism* ; Receptors, Cannabinoid ; Time Factors ; Wound Healing/physiology*

BACKGROUND/AIMS: MicroRNAs (miRNAs) were reported to be responsible for intestinal permeability in diarrhea-predominant irritable bowel syndrome (IBS-D) rats in our previous study. However, whether and how miRNAs regulate visceral hypersensitivity in IBS-D remains largely unknown. METHODS: We established the IBS-D rat model and evaluated it using the nociceptive visceral hypersensitivity test, myeloperoxidase activity assay, restraint stress-induced defecation, and electromyographic (EMG) activity. The distal colon was subjected to miRNA microarray analysis followed by isolation and culture of colonic epithelial cells (CECs). Bioinformatic analysis and further experiments, including dual luciferase assays, quantitative real-time polymerase chain reaction, western blot, and enzyme-linked immunosorbent assay, were used to detect the expression of miRNAs and how it regulates visceral hypersensitivity in IBS-D rats. RESULTS: The IBS-D rat model was successfully established. A total of 24 miRNAs were differentially expressed in the distal colon of IBS-D rats; 9 were upregulated and 15 were downregulated. Among them, the most significant upregulation was miR-200a, accompanied by downregulation of cannabinoid receptor 1 (CNR1) and serotonin transporter (SERT). MiR-200a mimic markedly inhibited the expression of CNR1/SERT. Bioinformatic analysis and luciferase assay confirmed that CNR1/SERT are direct targets of miR-200a. Rescue experiments that overexpressed CNR1/SERT significantly abolished the inhibitory effect of miR-200a on the IBS-D rats CECs. CONCLUSIONS: This study suggests that miR-200a could induce visceral hyperalgesia by targeting the downregulation of CNR1 and SERT, aggravating or leading to the development and progression of IBS-D. MiR-200a may be a regulator of visceral hypersensitivity, which provides potential targets for the treatment of IBS-D.
Animals ; Blotting, Western ; Colon ; Computational Biology ; Defecation ; Diarrhea ; Down-Regulation ; Enzyme-Linked Immunosorbent Assay ; Epithelial Cells ; Hyperalgesia ; Hypersensitivity ; Irritable Bowel Syndrome ; Luciferases ; Microarray Analysis ; MicroRNAs ; Models, Animal ; Permeability ; Peroxidase ; Rats ; Real-Time Polymerase Chain Reaction ; Receptors, Cannabinoid ; Serotonin Plasma Membrane Transport Proteins ; Serotonin ; Up-Regulation