Expression Of CB1R Research Articles

Inhibition of CB1R in the Hypothalamic Paraventricular Nucleus Ameliorates Hypertension Through Wnt/β-Catenin/RAS Pathway.

The hypothalamic paraventricular nucleus (PVN), as an important integrating center, plays a prominent role in the pathogenesis of hypertension, in maintaining the stability of cardiovascular activity through peripheral sympathetic nervous activity and secretion of various humoral factors. Acknowledging that the mechanistic targets of the endocannabinoid type 1 receptor (CB1R) are the key signaling systems involved in the regulation of hypertension, we sought to clarify whether inhibition of CB1R within the PVN ameliorates hypertension through Wnt/β-catenin/RAS pathway. Spontaneously hypertensive rats (SHRs) and Wistar Kyoto rats were randomly assigned to different groups and treated with bilateral PVN injections of AM251 (CB1R antagonist, 10µg/h) or vehicle (artificial cerebrospinal fluid, aCSF) for four weeks. Bilateral PVN injections of AM251 significantly decreased the heart rate, the body weight and the mean arterial pressure in SHRs. AM251 lowered the expression of CB1R, Wnt3, active-β-catenin, p-IKKβ, RAS components, pro-inflammatory cytokines and elevated the expression level of Glycogen synthase kinase3β and Superoxide Dismutase in the PVN of hypertensive rats. Our findings suggest that inhibition of CB1R in the PVN ameliorates hypertension through Wnt/β-catenin/RAS pathway and broaden our current understanding of the pathological mechanism and clinical treatment of hypertension.

Early life stress induces decreased expression of CB1R and FAAH and epigenetic changes in the medial prefrontal cortex of male rats.

Several studies in both animal models and in humans have provided substantial evidence that early life stress (ELS) induces long-term changes in behavior and brain function, making it a significant risk factor in the aetiology of various mental disorders, including anxiety and depression. In this study, we tested the hypothesis that ELS in male rats (i) leads to increased anxiety and depressive-like symptoms; and (ii) that these behavioral changes are associated with functional alterations in the endocannabinoid system of the medial prefrontal cortex (mPFC). We further assessed whether the predicted changes in the gene expression of two key components of the endocannabinoid system, cannabinoid receptor 1 (CB1R) and the fatty acid amide hydrolase (FAAH), are regulated by epigenetic mechanisms. Behavioral profiling revealed that the proportion of behaviorally affected animals was increased in ELS exposed male rats compared to control animals, specifically showing symptoms of anhedonia and impaired social behavior. On the molecular level we observed a decrease in CB1R and FAAH mRNA expression in the mPFC of adult ELS exposed animals. These gene expression changes were accompanied by reduced global histone 3 acetylation in the mPFC, while no significant changes in DNA methylation and no significant changes of histone-acetylation at the promoter regions of the analyzed genes were detected. Taken together, our data provide evidence that ELS induces a long-term reduction of CB1R and FAAH expression in the mPFC of adult male rats, which may partially contribute to the ELS-induced changes in adult socio-emotional behavior.

Regulation of targeted blocking cannabinoid receptor 1 on spleen immune function and inflammatory response in mice under chronic intermittent hypoxia

Objective: To observe the effects of targeting and blocking cannabinoid receptor 1 (CB1R) on mouse spleen immune function and inflammatory response under chronic intermittent hypoxia (CIH) conditions, and to explore its regulatory effort. Methods: Forty SPF male C57BL/6 mice aged 4 to 5 weeks,from May 2021 to August 2021 in Experimental Animal Center of the Second Hospital of Shanxi Medical University, were randomly divided into normal oxygen control group (NC), 6-week CIH group (6w CIH), 10-week CIH group (10w CIH), 6-week CIH+CB1R group (6w CIH+AM251) and 10-week CIH+CB1R group (10w CIH+AM251) according to the method of random number table. The advanced programmable intermittent low oxygen chamber was used to prepare the CIH mouse model. The morphological structure of spleen tissue of CIH mice was stained by hematoxylin-eosin (HE) staining. The expression levels of M1 and M2 macrophage surface markers CD86, CD206 were determined by immunofluorescence. The mRNA expression levels of CB1R, CD86, CD206 and the relative expression levels of RORγt and Foxp3,which are characteristic transcriptional regulators of T helper 17(Th17) and Treg cells were detected by quantitative reverse transcriptase PCR(qRT-PCR). The expression of inflammatory factors IL-6 and IL-10 was determined by ELISA. SPSS 26.0 and Graphpad prism 8.3 were used to analyze the data. Results: (1) Compared with NC group, spleen tissue structure was disordered, fibrous tissue hyperplasia, lymphocyte proliferation and disordered arrangement in periarteriole lymphatic sheath in CIH group. The expression of CB1R in CIH group was higher than that in NC group (P<0.05), and with the prolongation of CIH time, the expression of 10w CIH group was higher than that in 6w CIH group(P<0.05). The expression of CB1R in CIH+AM251 group was lower than that in the corresponding CIH group(all P<0.05). (2) Compared with NC group, the expression level of CD86 in macrophages in CIH group was higher than that in NC group(all P<0.05). The relative expression of RORγt in 6w and 10w CIH groups was 0.76±0.03 and 0.91±0.04, respectively, which was higher than that in NC group (0.65±0.06)(all P<0.05). The relative expression levels of inflammatory factor IL-6 were 10.80±1.73 and 14.86±0.01, respectively, which were higher than 6.69±0.23 in the NC group (all P<0.05). The expression level of CD206 in macrophages in the CIH+AM251 group was higher than that in the CIH group(all P<0.05). The relative expression levels of Foxp3 in 6w and 10w CIH+AM251 groups were 0.62±0.05 and 0.32±0.21, respectively, which were higher than those in 6w CIH group (0.28±0.02) and 10w CIH group (0.02±0.01)(P<0.05). The relative expression levels of anti-inflammatory factor IL-10 were 668.45±15.71 and 379.15±56.84, respectively, which were higher than those in CIH group (all P<0.05). Conclusion: Targeted sealing of CB1R may alleviate inflammatory response of mouse spleen under CIH conditions by regulating macrophage polarization and the expression of inflammatory factors, and may have some protective effect.

Gut Microbiota-Mediated Alterations of Hippocampal CB1R Regulating the Diurnal Variation of Cognitive Impairment Induced by Hepatic Ischemia-Reperfusion Injury in Mice.

Patients suffering from hepatic ischemia-reperfusion injury (HIRI) frequently exhibit postoperative cognitive deficits. Our previous observations have emphasized the diurnal variation in hepatic ischemia-reperfusion injury-induced cognitive impairment, in which gut microbiota-associated hippocampal lipid metabolism plays an important role. Herein, we further investigated the molecular mechanisms involved in the process. Hepatic ischemia-reperfusion surgery was performed under morning (ZT0, 08:00) and evening (ZT12, 20:00). Fecal microbiota transplantation was used to associate HIRI model with pseudo-germ-free mice. The novel object recognition test and Y-maze test were used to assess cognitive function. 16S rRNA gene sequencing and analysis were used for microbial analysis. Western blotting was used for hippocampal protein analysis. Compared with the ZT0-HIRI group, ZT12-HIRI mice showed learning and short term memory impairment, accompanied by down-regulated expression of hippocampal CB1R, but not CB2R. Both gut microbiota composition and microbiota metabolites were significantly different in ZT12-HIRI mice compared with ZT0-HIRI. Fecal microbiota transplantation from the ZT12-HIRI was demonstrated to induce cognitive impairment behavior and down-regulated hippocampal CB1R and β-arrestin1. Intraperitoneal administration of CB1R inhibitor AM251 (1mg/kg) down-regulated hippocampal CB1R and caused cognitive impairment in ZT0-HIRI mice. And intraperitoneal administration of CB1R agonist WIN 55,212-2 (1mg/kg) up-regulated hippocampal CB1R and improved cognitive impairment in ZT12-HIRI mice. In summary, the results suggest that gut microbiota may regulate the diurnal variation of HIRI-induced cognitive function by interfering with hippocampal CB1R.

SGIP1 binding to the α-helical H9 domain of cannabinoid receptor 1 promotes axonal surface expression.

Endocannabinoid signalling mediated by cannabinoid receptor 1 (CB1R, also known as CNR1) is critical for homeostatic neuromodulation of both excitatory and inhibitory synapses. This requires highly polarised axonal surface expression of CB1R, but how this is achieved remains unclear. We previously reported that the α-helical H9 domain in the intracellular C terminus of CB1R contributes to axonal surface expression by an unknown mechanism. Here, we show in rat primary neuronal cultures that the H9 domain binds to the endocytic adaptor protein SGIP1 to promote CB1R expression in the axonal membrane. Overexpression of SGIP1 increases CB1R axonal surface localisation but has no effect on CB1R lacking the H9 domain (CB1RΔH9). Conversely, SGIP1 knockdown reduces axonal surface expression of CB1R but does not affect CB1RΔH9. Furthermore, SGIP1 knockdown diminishes CB1R-mediated inhibition of presynaptic Ca2+ influx in response to neuronal activity. Taken together, these data advance mechanistic understanding of endocannabinoid signalling by demonstrating that SGIP1 interaction with the H9 domain underpins axonal CB1R surface expression to regulate presynaptic responsiveness.

Cannabinoid receptors as new targets for HTLV-1 associated myelopathy (HAM/TSP) treatment

Background/AimThe roles of endocannabinoids are described in immune modulation and neuroprotection. HTLV-1-associated myelopathy (HAM/TSP) is an inflammatory neurodegenerative disease. Therefore, in this study, the interactions of HTLV-1 regulatory factors and host cannabinoid receptors (CBRs) were evaluated in HAM/TSP. MethodsNineteen HAM/TSPs, 22 asymptomatic carriers (ACs), and 18 healthy controls (HCs) were enrolled. RNA was extracted from PBMCs and then reverse-transcribed to cDNA. The gene expression of CB1R and CB2R, as well as HTLV-1 proviral load (PVL), Tax and HTLV-1 basic leucine zipper factor (HBZ) were assessed by RT-qPCR. ResultsThe mean expression of CB1R in ACs (8.51 ± 2.76) was significantly higher than HAMTSPs (1.593 ± 0.74, p = 0.05) and also HCs (0.10 ± 0.039, p = 0.001). The CB2R gene expression level in ACs (2.62±0.44) was significantly higher than HAM/TSPs (0.59 ± 0.15, p = 0.001) and HCs (1.00 ± 0.2, p = 0.006). Meanwhile there was a strong correlation between CB1R and CB2R gene expression levels in the HCs and HAM/TSPs (p = 0.001). HTLV-1-Tax expression in HAM/TSPs (386 ± 104) was higher than ACs (75 ± 32) and statistically significant (p = 0.003). While HTLV-1-HBZ was only expressed in three AC subjects and five HAM/TSPs, thus it cannot be analyzed. ConclusionThe up-regulation of CB2R has immunomodulatory effects in inflammatory reactions. While CB1R as a neuroprotective agent may suppress inflammatory reactions in ACs, preventing HAM/TSP. It seems that, like multiple sclerosis (MS), cannabinoid medications are beneficial in HAM/TSP.

Laminar Distribution of Cannabinoid Receptor 1 in the Prefrontal Cortex of Nonhuman Primates.

Cannabis is an annual herb of the genus Cannabis, with a history of medical use going back thousands of years. However, its abuse causes many side-effects, including confusion of consciousness, alienation, and mental disorders such as schizophrenia and depression. Research conducted on rodents suggests that there are two types of cannabinoid receptors-cannabinoid receptor 1 (CB1R) and cannabinoid receptor 2 (CB2R). CB1R is found mostly in the central nervous system, particularly in the prefrontal cortex (PFC), and alterations in its expression in the PFC have been strongly linked to mental disorders. Within the layers of the PFC, Brodmann area 46 is associated with the processing of complex cognitive information. However, it remains unclear whether CB1R is expressed in the PFC 46 area of non-human primate. In this work, we applied western blotting along with immunofluorescent histochemical staining to investigate the distribution pattern of CB1R in the PFC of nonhuman primate, Our findings reveal that CB1R is highly expressed in the monkey PFC, especially in area 46. Furthermore, CB1R exhibits a layered distribution pattern within area 46 of the PFC, with the inner granular layer displaying the highest expression levels. Additionally, CB1R+PV+ cells are widely distributed in lay II-VI of area 46, with layer IV showing notable prevalence. In conclusion, CB1R is distributed in the PV interneurons in area 46 of the prefrontal cortex, particularly in layer IV, suggesting that cannabis may modulate PFC activities via regulating interneuron in the PFC. And cannabis-induced side effects may be caused by abnormal expression of CB1R.

Expression of Cannabinoid Receptors in the Trigeminal Ganglion of the Horse.

Cannabinoid receptors are expressed in human and animal trigeminal sensory neurons; however, the expression in the equine trigeminal ganglion is unknown. Ten trigeminal ganglia from five horses were collected post-mortem from an abattoir. The expression of cannabinoid receptors type 1 (CB1R) and type 2 (CB2R), and the cannabinoid-related receptors like transient receptor potential vanilloid type 1 (TRPV1), peroxisome proliferator-activated receptor gamma (PPARɣ), and G protein-related receptor 55 (GPR55) in the trigeminal ganglia (TG) of the horse were studied, using immunofluorescence on cryosections and formalin-fixed paraffin-embedded (FFPE) sections. Neurons and glial cells were identified using fluorescent Nissl staining NeuroTrace® and an antibody directed against the glial marker glial fibrillary acidic protein (GFAP), respectively. Macrophages were identified by means of an antibody directed against the macrophages/microglia marker ionized calcium-binding adapter molecule 1 (IBA1). The protein expression of CB1R, CB2R, TRPV1, and PPARɣ was found in the majority of TG neurons in both cryosections and FFPE sections. The expression of GPR55 immunoreactivity was mainly detectable in FFPE sections, with expression in the majority of sensory neurons. Some receptors were also observed in glial cells (CB2R, TRPV1, PPARγ, and GPR55) and inflammatory cells (PPARγ and GPR55). These results support further investigation of such receptors in disorders of equine trigeminal neuronal excitability.

Increased hippocampal cannabinoid 1 receptor expression is associated with protection from severe seizures in pregnant mice with reduced uterine perfusion pressure.

Eclampsia, new-onset seizures in pregnancy, can complicate preeclampsia, a hypertensive pregnancy disorder. The mechanisms contributing to increased risk of seizures in preeclampsia are not fully known. One mechanism could be abnormal endocannabinoid system (ECS) activity and impaired neuromodulation. Indeed, increased placental cannabinoid receptor 1 (CB1R) expression and reduced serum anandamide, a CB1R ligand, have been reported in preeclampsia patients. We hypothesized that reduced uterine perfusion pressure (RUPP), used to mimic preeclampsia, leads to changes in hippocampal CB1R expression, and that manipulating CB1R activity will change seizure severity in RUPP mice. Pregnant mice underwent sham or RUPP surgery on gestational day (GD)13.5. On GD18.5, mice received: no drug treatment, pentylenetetrazol (PTZ, 40 mg/kg), Rimonabant (10 mg/kg) + PTZ, or 2-AG (1 mg/kg) + PTZ. Behaviors were video recorded (15 min for Rimonabant and 2-AG, followed by 30 min for PTZ), and the hippocampus was harvested. The expression of CB1R and ECS proteins was measured in hippocampal homogenates, synaptosomes, and cytosol. Hippocampal CB1R increased in homogenates and cytosolic fraction, and was unchanged in synaptosomes of RUPP mice. Increased CB1R colocalization on glutamate-releasing neurons within hippocampal CA1 was observed in RUPP mice. Rimonabant modestly increased seizure scores over time in RUPP mice. PTZ after rimonabant pretreatment increased seizure scores and duration, while reducing latency in sham mice, with little to no change in RUPP mice. Furthermore, RUPP mice had lower seizure scores over time than sham following CB1R blockade and activation. These data suggest that RUPP modifies CB1R activity prior to seizure induction, which protects mice from worse seizure outcomes.

The clinical and pathological significance of increased expression of the cannabinoid receptors CB-1R and CB-2R in patients with papillary thyroid carcinomas compared to benign thyroid lesions.

Papillary thyroid carcinoma is the most common malignancy of the endocrine system. Most papillary thyroid carcinoma patients enjoy excellent outcomes. However, in patients with biologically aggressive features, additional prognostic and predictive data may aid disease management. Dysregulation of the endocannabinoid system including the cannabinoid receptors 1 and 2 (CB-1R and CB-2R) during carcinogenesis has been extensively studied over the last few decades. The aim of this study was to evaluate immunohistochemically the expression levels of both receptors in patients with papillary thyroid carcinoma and benign diseases, and to compare these rates and the histopathologically and clinically prognostic features. The pathological materials and clinical data of 100 patients with papillary thyroid carcinoma and 40 with benign diseases were retrospectively re-evaluated. All tissues were immunohistochemically stained for CB-1R and CB-2R. The expression levels of CB-1R and CB-2R in papillary thyroid carcinomas, and benign lesions were recorded and compared with the pathological and clinical features. The expression levels of both receptors were significantly higher in papillary thyroid carcinoma patients than in those with benign conditions (P = 0.001). CB-1R expression correlated with both extrathyroidal extension (P = 0.022) and capsular invasion (P = 0.001). CB-2R expression was associated with the risk group of the American Thyroid Association stratification system (P = 0.004). Our study suggests that increased cannabinoid receptor expression contributes to thyroid carcinogenesis. The CB-2R expression level could provide additional information aiding risk management. Furthermore, the CB-1R and CB-2R antibodies might increase the accuracy of papillary thyroid carcinoma diagnosis when combined with the papillary thyroid carcinoma biomarkers assayed after fine-needle aspiration of neoplastic cells.

CB1R chronic intermittent pharmacological activation facilitates amphetamine seeking and self-administration and changes in CB1R/CRFR1 expression in the amygdala and nucleus accumbens in rats

Patterns of drug ingestion may have a dissimilar impact on the brain, and therefore also the development of drug addiction. One pattern is binge intoxication that refers to the ingestion of a high amount of drug on a single occasion followed by an abstinence period of variable duration. In this study, our goal was to contrast the effect of continuous low amounts with intermittent higher amounts of Arachidonyl-chloro-ethylamide (ACEA), a CB1R agonist, on amphetamine seeking and ingestion, and describe the effects on the expression of CB1R and CRFR1 in the central nucleus of the amygdala (CeA) and in the nucleus accumbens shell (NAcS). Adult male Wistar rats were treated with a daily administration of vehicle or 20 μg of ACEA, or four days of vehicle followed by 100 μg of ACEA on the fifth day, for a total of 30 days. Upon completion of this treatment, the CB1R and CRFR1 expression in the CeA and NAcS was evaluated by immunofluorescence. Additional groups of rats were evaluated for their anxiety levels (elevated plus maze, EPM), amphetamine (AMPH) self-administration (ASA) and breakpoint (A-BP), as well as AMPH-induced conditioned place preference (A-CPP). Results indicated that ACEA induced changes in the CB1R and CRFR1 expression in both the NAcS and CeA. An increase in anxiety-like behavior, ASA, A-BP and A-CPP was also observed. Since the intermittent administration of 100 μg of ACEA induced the most evident changes in most of the parameters studied, we concluded that binge-like ingestion of drugs induces changes in the brain that may make the subject more vulnerable to developing drug addiction.

Reduced uterine perfusion increases hippocampal cannabinoid receptor 1 expression and reduces pentylenetetrazol-induced seizures after rimonabant pre-treatment

Eclampsia, new-onset seizures in pregnant women, can affect women with preeclampsia, a hypertensive pregnancy disorder. Eclampsia is associated with high maternal and fetal morbidity and mortality. The mechanisms contributing to increased risk of seizures in preeclampsia patients are not fully known. One potential mechanism could be abnormal endocannabinoid system activity, and abnormal neuro-modulation. Indeed, increased placental cannabinoid receptor 1 (CB1R) expression and reduced serum concentration of anandamide, a ligand that activates the CB1R, have been reported in preeclampsia patients. We hypothesized that reduced uterine perfusion pressure (RUPP) in mice leads to differences in hippocampal CB1R expression and that inhibiting CB1R activity will increase seizure sensitivity in RUPP mice. Pregnant mice underwent sham (n=5) or RUPP (n=5) surgery on gestational day (GD) 13.5. On GD 18.5, the hippocampus was harvested and processed for Western blot to analyze the expression of CB1R in homogenates, synaptosomal fraction, and cytosolic fraction of the hippocampus. To determine if blocking CB1R increases sensitivity to pentylenetetrazol (PTZ)-induced seizures, additional sham (n=7) and RUPP (n=7) mice were pretreated with 10 mg/kg of rimonabant, video monitored for 15 minutes, injected with 40 mg/kg of PTZ and video monitored for an additional 30 minutes before being sacrificed. Seizures were scored using a modified 7-point Racine scale. In hippocampal homogenates, CB1R expression increased in RUPP mice (p=0.056). There was no difference in CB1R expression in the synaptosomal fraction (p=0.095); however, there was an increase in CB1R expression in the cytosolic fraction of RUPP mice (p=0.016). Immunofluorescence analysis showed increased CB1R colocalization on both glutamate- and GABA- releasing neurons within hippocampal CA1 (p=0.029; p=0.057, respectively). CB1R blockade induced a maximum seizure score of 4 in both groups but led to higher seizure scores over time in RUPP mice (p=0.025). PTZ injection after rimonabant pretreatment increased seizure scores in sham (p&lt;0.05), non-significantly increased scores in RUPP (p=0.075), increased duration of seizures in sham but not RUPP mice (p=0.021; p=0.245, respectively), and reduced latency to seizures in sham mice (p=0.019) while there was no further decrease in seizure latency in RUPP (p=0.374) mice. Furthermore, during the first 15 minutes of PTZ exposure, RUPP mice had lower seizure scores over time than sham [p(TimexRUPP)=0.002] following CB1R blockade. These data suggest that RUPP induces abnormal CB1R expression, resulting in increased sensitivity to seizures after CB1R blockade, while protecting against worse seizures when challenged with the pro-convulsant, PTZ. NIH R00HL129192, R00HL129192-S1, COBRE Pilot Grant, T32HL105324, William Townsend Porter Pre-Doctoral Fellowship from the American Physiological Society, 1F99NS129125-01. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Cannabinoid Receptor Agonist WIN55, 212-2 Attenuates Injury in the Hippocampus of Rats after Deep Hypothermic Circulatory Arrest

Postoperative neurological deficits remain a challenge in cardiac surgery employing deep hypothermic circulatory arrest (DHCA). This study aimed to investigate the effect of WIN55, 212-2, a cannabinoid agonist, on brain injury in a rat model of DHCA. Twenty-four male Sprague Dawley rats were randomly divided into three groups: a control group (which underwent cardiopulmonary bypass (CPB) only), a DHCA group (CPB with DHCA), and a WIN group (WIN55, 212-2 pretreatment before CPB with DHCA). Histopathological changes in the brain were evaluated by hematoxylin-eosin staining. Plasma levels of superoxide dismutase (SOD) and proinflammatory cytokines including interleukin (IL)-1β, IL-6, and tumor necrosis factor-alpha (TNF-a) were determined using an enzyme-linked immunosorbent assay (ELISA). The expression of SOD in the hippocampus was detected by Western blot and immunofluorescence staining. Levels of apoptotic-related protein caspase-3 and type 1 cannabinoid receptor (CB1R) in the hippocampus were evaluated by Western blot. WIN55, 212-2 administration attenuated histopathological injury of the hippocampus in rats undergoing DHCA, associated with lowered levels of IL-1β, IL-6, and TNF-α (p < 0.05, p < 0.001, and p < 0.01, vs. DHCA, respectively) and an increased level of SOD (p < 0.05 vs. DHCA). WIN55, 212-2 treatment also increased the content of SOD in the hippocampus. The protein expression of caspase-3 was downregulated and the expression of CB1R was upregulated in the hippocampus by WIN55, 212-2. the administration of WIN55, 212-2 alleviates hippocampal injury induced by DHCA in rats by regulating intrinsic inflammatory and oxidative stress responses through a CB1R-dependent mechanism.

Cannabidiol interacts with the FXR/Nrf2 pathway and changes the CB1/CB2 receptors ratio in gentamicin-induced kidney injury in rats.

Gentamicin-induced nephrotoxicity was used as an experimental model of kidney disease. The present study was performed to assess the therapeutic role of cannabidiol (CBD) against gentamicin-induced renal damage. Forty two male Wistar rats were randomly allocated into 6 groups (n=7), including: (1) Control, (2) Vehicle, (3) Gentamicin-treated group (100 mg/kg/day) for 10 days (GM), (4-6) 3 Gentamicin-CBD-treated groups (2.5, 5, and 10 mg/kg/day) for 10 days (GM+CBD2.5, GM+CBD5, GM+CBD10). Serum levels of BUN and Cr, renal histology as well as real-time qRT-PCR were used to investigate the pattern of changes at different levels. Gentamicin increased serum BUN and Cr (P<0.001), down-regulation of FXR (P<0.001), SOD (P<0.05) and up-regulation of CB1 receptor mRNA (P<0.01). Compared to the control group, CBD at 5 decreased (P<0.05) and at 10 mg/kg/day increased the expression of FXR (P<0.05). Nrf2 expression in CBD groups was increased (P<0.001 vs. GM). The expression of TNF-α compared to the control and GM groups, was significantly increased in CBD2.5 (P<0.01) and CBD10 (P<0.05). Compared to the control, CBD at 2.5 (P<0.01), 5 (P<0.001) and 10 (P<0.001) mg/kg/day significantly increased the expression of CB1R. Up-regulation of CB1R in the GM+CBD5, was significantly higher (P<0.05) than the GM group. Compared to the control group, the most significant increase in CB2 receptor expression was observed at CBD10 (P<0.05). CBD particularly at 10 mg/kg/day might be of significant therapeutic benefit against such renal complications. Activating the FXR/Nrf2 pathway and counteracting the deleterious effects of CB1 receptors via CB2 receptors scale-up could be part of the protective mechanisms of CBD.

Treadmill Exercise Prevents Cognitive Impairments in Adolescent Intermittent Ethanol Rats by Reducing the Excessive Activation of Microglia Cell in the Hippocampus

The excessive activation of microglia cell induced by adolescent intermittent ethanol (AIE) leads to neuroinflammation in the hippocampus. The endocannabinoid system plays a key role in the modulation of microglia activation. Accumulating evidence suggests that regular exercise improves learning and memory deficits in AIE models. The purpose of this study was to explore the effects of treadmill exercise intervention on the cognitive performance, activation of microglia cells and the expression of monoacylglycerol lipase (MAGL), cannabinoid receptor type 1 (CB1R) and cannabinoid receptor type 2 (CB2R) in the hippocampus of AIE rats. Here, we show that AIE rats exhibited cognitive impairments, whereas the treadmill exercise improves the cognitive performance in AIE rats. In order to explore the possible mechanisms for the exercise-induced attenuation of cognitive disorder, we examined the neuroinflammation in the hippocampus. We found that treadmill exercise led to the decrease in the level of proinflammatory cytokines (IL-1β, IL-6 and TNF-α) and the increase in the level of anti-inflammatory cytokine (IL-10). In addition, we found that treadmill exercise reduced the excessive activation of the microglia cell in the hippocampus of AIE rats. Finally, we found that AIE led to a decrease in the expression of CB1R and CB2R in the hippocampus; however, the treadmill exercise further decreased the expression of CB2R in the hippocampus of AIE rats. Our results suggest that treadmill exercise attenuates AIE-induced neuroinflammation and the excessive activation of hippocampus microglial cells, which may contribute to the exercise-induced improvement of cognitive performance in AIE rats.

Role of Type I Cannabinoid Receptor in Sensory Neurons in Psoriasiform Skin Inflammation and Pruritus

Type I cannabinoid receptor (CB1R) has been reported to exhibit favorable anti-inflammation and antipruritus effects against inflammation-based skin diseases, but the specific mechanism remains to be explored. In this study, we found that the activation of CB1R significantly relieved the scratching behavior and skin inflammation in a psoriatic mouse model, whereas CB1R antagonist aggravated these symptoms. Because the expression of CB1R was abundant in dorsal root ganglia, we constructed mice with conditional CB1R knockout in primary sensory neurons and found that imiquimod-induced psoriasiform inflammation and itch were both worsened in CB1R-conditional knockout mice. Next, we observed that the CB1R was mostly located in peptidergic neurons, and deletion of CB1R in primary sensory neurons promoted the production and release of substance P to the skin tissue. Furthermore, the elevated substance P in the skin affected the activation of extracellular signal‒regulated kinase in keratinocytes and induced the accumulation of mast cells in the dermis. Finally, we showed that blocking the substance P signal significantly alleviated the exacerbation of psoriasiform inflammation and itch caused by imiquimod in CB1R-conditional knockout mice. Together, our work reveals that CB1R in sensory neurons plays a key role in psoriasiform skin inflammation and pruritus by regulating substance P expression.

Dominance status is associated with a variation in cannabinoid receptor 1 expression and amphetamine reward

The rewarding effects of psychostimulants appear to be distinct between dominant and subordinate individuals. In turn, the endocannabinoid system is an important modulator of drug reward in the nucleus accumbens and medial prefrontal cortex, however the connection with social dominance is yet to be established. Male rats were classified as dominant or subordinate on the basis of their spontaneous agonistic interactions and drug reward was assessed by means of conditioned place preference with amphetamine (AMPH). In addition, the expression of CB1R, CB2R, FAAH1, and DAGLa was quantified from accumbal and cortical tissue samples. Our findings demonstrate that dominant rats required a lesser dose of AMPH to acquire a preference for the drug-associated compartment, thereby suggesting a higher sensitivity to the rewarding effects of AMPH. Furthermore, dominants exhibited a lower expression of CB1R in the medial prefrontal cortex and nucleus accumbens. This study illustrates how CBR1 expression could differentiate the behavioral phenotypes associated to social dominance.

Protective Effects of Cannabis sativa on chemotherapy-induced nausea in a rat: Involvement of CB1 receptors.

Cyclophosphamide is an anticancer and immunosuppressive agent used in the treatment of various malignancies but causing gastrointestinal distress. Cannabis sativa and its derivatives have been used for the treatment of human gastrointestinal disorders. A purpose of this study was to investigate the effect of C. sativa on nausea induced by cyclophosphamide in rats. The rats were divided into four groups (eight animals per group): Group 1: Normal control (saline i.p.). Group 2: Rats received cyclophosphamide (200 mg/kg i.p.) 3 consecutive days. Group 3 and 4: Rats received cyclophosphamide (200 mg/kg i.p.) across Days 1-7, and C. sativa (20 and 40 mg/kg s.c.) was administered on cyclophosphamide days 4-7. We examined intake of kaolin, normal food and changes in body weight, as an indicator of the emetic stimulus. Oxidative stress markers, antioxidant enzymes status, serotonin (5-HT), dopamine, noradrenaline and CB1R levels were evaluated in the intestinal homogenate. Moreover, histopathological study was performed. Results showed that C. sativa ameliorates cyclophosphamide-induced emesis by increasing in body weight and normal diet intake with a decrease in kaolin diet intake after 7 days. Moreover, C. sativa significantly decreases (serotonin) 5-HT, dopamine and noradrenaline, as well as decreasing oxidative stress and inflammation. Administration of C. sativa significantly increased the expression of CB1R in intestinal homogenate. Treatment with C. sativa also improved the histological feature of an intestinal tissue. These results suggested that C. sativa possess antiemetic, antioxidant and anti-inflammatory effects in chemotherapy-induced nausea in rats by activating CB1R.

CB1R-stabilized NLRP3 inflammasome drives antipsychotics cardiotoxicity

Long-term use of antipsychotics is a common cause of myocardial injury and even sudden cardiac deaths that often lead to drug withdrawn or discontinuation. Mechanisms underlying antipsychotics cardiotoxicity remain largely unknown. Herein we performed RNA sequencing and found that NLRP3 inflammasome-mediated pyroptosis contributed predominantly to multiple antipsychotics cardiotoxicity. Pyroptosis-based small-molecule compound screen identified cannabinoid receptor 1 (CB1R) as an upstream regulator of the NLRP3 inflammasome. Mechanistically, antipsychotics competitively bond to the CB1R and led to CB1R translocation to the cytoplasm, where CB1R directly interacted with NLRP3 inflammasome via amino acid residues 177–209, rendering stabilization of the inflammasome. Knockout of Cb1r significantly alleviated antipsychotic-induced cardiomyocyte pyroptosis and cardiotoxicity. Multi-organ-based investigation revealed no additional toxicity of newer CB1R antagonists. In authentic human cases, the expression of CB1R and NLRP3 inflammasome positively correlated with antipsychotics-induced cardiotoxicity. These results suggest that CB1R is a potent regulator of the NLRP3 inflammsome-mediated pyroptosis and small-molecule inhibitors targeting the CB1R/NLRP3 signaling represent attractive approaches to rescue cardiac side effects of antipsychotics.

Cannabinoid Receptor‐Mediated Synaptic Signaling and Neural Plasticity in Central Olfactory Neurons

Our studies aim to understand integrative and computational mechanisms that allow main olfactory bulb neurons to respond to afferent input and synaptic or feedback signals. The endocannabinoid (eCB) signaling system has been functionally implicated in many brain regions but our understanding of the role of cannabinoid receptor type 1 (CB1R) in olfactory processing remains limited. Endocannabinoids are known to mediate retrograde signaling at synapses in several brain regions through a form of short‐term neural plasticity. Endocannabinoids are released from depolarized principal neurons and rapidly diffuse to presynaptic inhibitory interneurons to transiently reduce presynaptic firing and neurotransmitter (GABA) release (Depolarization‐Induced Suppression of Inhibition, DSI).We study the function of the endocannabinoid system in regulating neural activity at synapses in the main olfactory bulb, the first central relay station in the brain for the processing of olfactory information coming from the nose. Our experimental approach uses electrophysiological recording techniques, specifically whole cell patch‐clamp recordings. Previously, using anatomical approaches, we showed that CB1R is present in periglomerular processes of a GAD65‐positive population of interneurons but not in mitral cells, key output neurons. We detected eCBs in the mouse main olfactory bulb as well as the expression of CB1R and other genes associated with the cannabinoid signaling system.Output neurons such as mitral cells and tufted cells in the olfactory bulb are computational elements in brain circuits that integrate incoming signals with membrane properties to generate behaviorally relevant synaptic output. Our data support the notion that retrograde signaling is present in neural circuits involving mitral and tufted cells. Mitral and tufted cells release endocannabinoids and, through retrograde signaling, inhibit presynaptic interneurons such as periglomerular cells, which controls the GABA release of these presynaptic neurons. This, in turn, allows mitral and tufted cells to temporarily regulate their synaptic input and relieve them from synaptic inhibition. Endocannabinoids function as retrograde messengers to regulate neural signaling and mediate plasticity at olfactory bulb synapses with potential effects on olfactory threshold and behavior.