Expression Of Cannabinoid Receptors Research Articles

High omega arachidonic acid/docosahexaenoic acid ratio induces mitochondrial dysfunction and altered lipid metabolism in human hepatoma cells.

BACKGROUNDNon-alcoholic fatty liver disease (NAFLD) is a common cause of liver disease worldwide and is a growing epidemic. A high ratio of omega-6 fatty acids to omega-3 fatty acids in the diet has been implicated in the development of NAFLD. However, the inflicted cellular pathology remains unknown. A high ratio may promote lipogenic pathways and contribute to reactive oxygen species (ROS)-mediated damage, perhaps leading to mitochondrial dysfunction. Therefore, these parameters were investigated to understand their contribution to NAFLD development.AIMTo examine the effect of increasing ratios of omega-6:3 fatty acids on mitochondrial function and lipid metabolism mediators.METHODSHepG2-derived VL-17A cells were treated with normal (1:1, 4:1) and high (15:1, 25:1) ratios of omega-6: omega-3 fatty acids [arachidonic acid (AA): docosahexaenoic acid (DHA)] at various time points. Mitochondrial activity and function were examined via MTT assay and Seahorse XF24 analyzer, respectively. Triglyceride accumulation was determined by using EnzyChrom™ and levels of ROS were measured by fluorescence intensity. Protein expression of the mediators of lipogenic, lipolytic and endocannabinoid pathways was assessed by Western blotting.RESULTSHigh AA:DHA ratio decreased mitochondrial activity (P < 0.01; up to 80%) and promoted intracellular triglyceride accumulation (P < 0.05; 40%-70%). Mechanistically, it altered the mediators of lipid metabolism; increased the expression of stearoyl-CoA desaturase (P < 0.05; 22%-35%), decreased the expression of peroxisome proliferator-activated receptor-alpha (P < 0.05; 30%-40%) and increased the expression of cannabinoid receptor 1 (P < 0.05; 31%). Furthermore, the high ratio increased ROS production (P < 0.01; 74%-115%) and reduced mitochondrial respiratory functions such as basal and maximal respiration, ATP production, spare respiratory capacity and proton leak (P < 0.01; 35%-68%).CONCLUSIONHigh AA:DHA ratio induced triglyceride accumulation, increased oxidative stress and disrupted mitochondrial functions. Stimulation of lipogenic and steroidal transcription factors may partly mediate these effects and contribute to NAFLD development.

Histone methyltransferase G9a diminishes expression of cannabinoid CB1 receptors in primary sensory neurons in neuropathic pain

Type 1 cannabinoid receptors (CB1Rs) are expressed in the dorsal root ganglion (DRG) and contribute to the analgesic effect of cannabinoids. However, the epigenetic mechanism regulating the expression of CB1Rs in neuropathic pain is unknown. G9a (encoded by the Ehmt2 gene), a histone 3 at lysine 9 methyltransferase, is a key chromatin regulator responsible for gene silencing. In this study, we determined G9a's role in regulating CB1R expression in the DRG and in CB1R-mediated analgesic effects in an animal model of neuropathic pain. We show that nerve injury profoundly reduced mRNA levels of CB1Rs but increased the expression of CB2 receptors in the rat DRG. ChIP results indicated increased enrichment of histone 3 at lysine 9 dimethylation, a G9a-catalyzed repressive histone mark, at the promoter regions of the CB1R genes. G9a inhibition in nerve-injured rats not only up-regulated the CB1R expression level in the DRG but also potentiated the analgesic effect of a CB1R agonist on nerve injury-induced pain hypersensitivity. Furthermore, in mice lacking Ehmt2 in DRG neurons, nerve injury failed to reduce CB1R expression in the DRG and to decrease the analgesic effect of the CB1R agonist. Moreover, nerve injury diminished the inhibitory effect of the CB1R agonist on synaptic glutamate release from primary afferent nerves to spinal cord dorsal horn neurons in WT mice but not in mice lacking Ehmt2 in DRG neurons. Our findings reveal that nerve injury diminishes the analgesic effect of CB1R agonists through G9a-mediated CB1R down-regulation in primary sensory neurons.

Cannabinoid receptor expression in non-small cell lung cancer. Effectiveness of tetrahydrocannabinol and cannabidiol inhibiting cell proliferation and epithelial-mesenchymal transition in vitro.

Background/ObjectivePatients with non-small cell lung cancer (NSCLC) develop resistance to antitumor agents by mechanisms that involve the epithelial-to-mesenchymal transition (EMT). This necessitates the development of new complementary drugs, e.g., cannabinoid receptors (CB1 and CB2) agonists including tetrahydrocannabinol (THC) and cannabidiol (CBD). The combined use of THC and CBD confers greater benefits, as CBD enhances the effects of THC and reduces its psychotropic activity. We assessed the relationship between the expression levels of CB1 and CB2 to the clinical features of a cohort of patients with NSCLC, and the effect of THC and CBD (individually and in combination) on proliferation, EMT and migration in vitro in A549, H460 and H1792 lung cancer cell lines.MethodsExpression levels of CB1, CB2, EGFR, CDH1, CDH2 and VIM were evaluated by quantitative reverse transcription-polymerase chain reaction. THC and CBD (10–100 μM), individually or in combination (1:1 ratio), were used for in vitro assays. Cell proliferation was determined by BrdU incorporation assay. Morphological changes in the cells were visualized by phase-contrast and fluorescence microscopy. Migration was studied by scratch recolonization induced by 20 ng/ml epidermal growth factor (EGF).ResultsThe tumor samples were classified according to the level of expression of CB1, CB2, or both. Patients with high expression levels of CB1, CB2, and CB1/CB2 showed increased survival reaching significance for CB1 and CB1/CB2 (p = 0.035 and 0.025, respectively). Both cannabinoid agonists inhibited the proliferation and expression of EGFR in lung cancer cells, and CBD potentiated the effect of THC. THC and CBD alone or in combination restored the epithelial phenotype, as evidenced by increased expression of CDH1 and reduced expression of CDH2 and VIM, as well as by fluorescence analysis of cellular cytoskeleton. Finally, both cannabinoids reduced the in vitro migration of the three lung cancer cells lines used.ConclusionsThe expression levels of CB1 and CB2 have a potential use as markers of survival in patients with NSCLC. THC and CBD inhibited the proliferation and expression of EGFR in the lung cancer cells studied. Finally, the THC/CBD combination restored the epithelial phenotype in vitro.

Involvement of endocannabinoid system, inflammation and apoptosis in diabetes induced liver injury: Role of 5-HT3 receptor antagonist

Confident relationships between diabetes andliver damagehave previously been established. This study was designed to evaluate hepaticinflammation, apoptosis, and endocannabinoid system alterations in diabetes with or withouttropisetrontreatment. Rats were assigned to five equal groups: control, tropisetron, diabetes, tropisetron+diabetes, and glibenclamide+diabetes (n = 7 in each group). Rats were treated with tropisetron (3 mg/kg) and glibenclamide (1 mg/kg) as a positive control for two weeks after type 1 diabetes induction.Inflammatory cytokines tumor necrosis factor-alpha and interleukin 6 (TNF-α and IL-6) levels, apoptotic cells, and fatty acid amide hydrolase (FAAH) enzyme, at both transcriptional and protein levels increased, while the gene expression of cannabinoid receptor 1 (CB1) and its protein level decreased in the diabetic liver compared to the control. Treatment with tropisetron reversed TNF-α, apoptotic index, and endocannabinoid system components. These effects were equipotent with glibenclamide, indicating that tropisetroncan protect liver tissue against diabetic disturbances. These findings strongly support the idea that diabetes-induced liver abnormality is mediated by inflammatory reactions, apoptosis, and endocannabinoid system, and that these effects can be alleviated by using tropisetron as an antioxidant and anti-inflammatory agent.

Stearoylethanolamide interferes with retrograde endocannabinoid signalling and supports the blood-brain barrier integrity under acute systemic inflammation

Neuroinflammation plays a prominent role in the onset of demyelinating diseases, major depressive disorder and delayed neurodegeneration. An open question remains whether pharmacological suppression of inflammation can effectively reduce the progression of these states. Bioactive lipid mediators such as N-acylethanolamines (NAEs) have an anti-inflammatory activity and are of pharmacological interest due to their endogenous on-demand production and the existence of distinct biological targets in humans and animals.Here we demonstrate for the first time, that treatment with stearoylethanolamide (SEA), a prevailing endogenously formed NAE, is neuroprotective against LPS-induced neuroinflammation in C57BL/6 male mice. SEA restricted the spreading of peripheral inflammation to the brain, and averted the activation of resident microglia and leukocyte trafficking to the brain parenchyma. Treatment with SEA per se increased the neuronal expression of cannabinoid receptors CB1/2 and brain levels of the most potent endogenous CB1/2 agonist 2-arachidonoylglycerol in vivo. SEA enhanced the amplitude of synaptic vesicle release, supported the balanced signal-to-noise ratio in glutamate- and GABAergic neurotransmission and decreased the excitotoxic risk associated with higher extracellular glutamate levels under neuroinflammation.The interference of SEA with the endocannabinoid system and presynaptic neurotransmitter release may represent an intrinsic neuroprotective mechanism that is triggered by inflammation and glutamate excitotoxicity. Thus, our data allows to consider SEA for the preventive therapy of acute and late-onset neuroinflammation-associated synaptic dysfunction and neurodegeneration.

Treadmill exercise improves LPS-induced memory impairments via endocannabinoid receptors and cyclooxygenase enzymes

Endocannabinoid system and cyclooxygenase enzymes are implicated in neuroinflammation-induced cognitive impairment. It is believed that non-pharmacological treatments such as physical exercise affect neural systems that control behavioral responses. This research examined the effects of treadmill aerobic exercise on the expression of cannabinoid receptors and cyclooxygenases against LPS-induced cognitive disorders in the hippocampus tissue of rats. For this purpose, rats received intraperitoneal injection of 0.25 mg/kg LPS or saline for 9 continuous days before exercise training. They again received a single i.p. injection with 0.5 mg/kg LPS or saline on days 20 and 41 after the beginning of exercise. The exercise groups were forced to run on a motorized treadmill 5 days per week for 8 weeks. After the last exercise training session, the water maze test was conducted to measure cognitive function. Finally, the hippocampus tissue samples of rats were removed and used to determine the levels of gene expression using the Real-Time PCR method. Data showed that the LPS-treated rats had longer escape distance and longer escape latency to reach the hidden platform and they spent less time than the other groups in the target quadrant, but exercise training improved them in the LPS + Exe (LPS + exercise) group. Exercise increased the expression of CB1 receptor in the Sal + Exe (saline + exercise) group and reduced the expression of CB2 receptor, COX-2 and mPGES-1 in the LPS + Exe group compared to the Sal + LPS group. The findings indicate that treadmill exercise may be beneficial for improvement of cognitive function by modulating the neuroinflammatory processes.

The effects of cannabis use on oral health.

Cannabis, also known as marijuana, is one of the most commonly used substances for medical and recreational purposes globally. With the trend of global legalization of medical use of cannabis and even the recreational use, the prevalence of recreational use of cannabis has increased markedly over the past few years. Correspondingly, the potential health concerns related to cannabis consumption have also increased. Therefore, it is necessary for oral healthcare providers to understand the effects of cannabis use on oral health. This review briefly summarizes the components of cannabis, biologic activities on tissues, and mechanisms of action in human cells and tissues. Oral tissue expression of cannabinoid receptors and the potential association of cannabis to oral diseases are also examined. The goals of this review are to (1) elaborate the basic biology and physiology of cannabis in human oral tissues, and (2) provide a better understanding the effects of its use and abuse on oral health. Due to insufficient information, more well-designed studies should be conducted. It is urgent to include cannabis usage into dental patient health records.

A multimodal investigation of cerebellar integrity associated with high-risk cannabis use.

With legalization efforts across the United States, cannabis use is becoming increasingly mainstream. Various studies have documented the effects of acute and chronic cannabis use on brain structure and cognitive performance, including within the frontal executive control network, but little attention has been given to the effects on the cerebellum. Recent evidence increasingly points to the role of the cerebellum in various nonmotor networks, and the cerebellum's expression of cannabinoid receptors may pose particular vulnerabilities to the consequences of cannabis use. Using a combined approach of resting-state functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI), the present study aims to assess how cannabis use relates to the cerebellum's intrinsic functional connectivity and underlying white matter structure and whether these properties are associated with craving or severity of cannabis use. Resting-state fMRI and DTI data, as well as self-reports of substance use history, were analyzed from a sample of 26 adults at risk for cannabis use disorder (CUD) and an age- and sex-matched comparison group of 25 cannabis-naïve adults (control). Results demonstrated that individuals at risk for a CUD showed key differences in cerebellar functional connectivity, with specific impacts on the dorsal attention and default mode networks. In addition, group differences in white matter were localized to the middle cerebellar peduncle (MCP), with a relationship between lower MCP diffusivity and higher levels of self-reported craving. These findings lend further support to the cerebellum's role in key cognitive networks and potential consequences for substance use disorders.

Expression of Cannabinoid Receptors in Myometrium and its Correlation With Dysmenorrhea in Adenomyosis.

The myometrium, especially the junctional zone (JZ), is now well documented to have a role in the pathogenesis of adenomyosis. Cannabinoid receptors have been shown to participate in the establishment of endometriosis and its pain perception. However, its relation to adenomyosis has not been identified yet. The aim of this study was to investigate the expression of cannabinoid receptor type I (CB1) and type II (CB2) in myometrium of uteri with and without adenomyosis and determine the correlation between their levels and clinical parameters of adenomyosis. We collected tissue samples of JZ and the outer myometrium from 45 premenopausal women with adenomyosis and 34 women without adenomyosis. CB1 and CB2 messenger RNA (mRNA) and protein expression levels were evaluated by the use of Western blotting and real-time quantitative polymerase chain reaction from all samples. Clinical information on the severity of dysmenorrhea and other data were collected. We found both CB1 and CB2 mRNA and protein levels in women with adenomyosis were significantly higher than those of controls, and CB1 expression levels in JZ were positively correlated with the severity of dysmenorrhea. These data suggest that cannabinoid receptor CB1 may be involved in the pathogenesis of dysmenorrhea in adenomyosis and may be a potential therapeutic target.

Chronic exercise modulates the cellular immunity and its cannabinoid receptors expression.

The impact of performing exercise on the immune system presents contrasting effects on health when performed at different intensities. In addition, the consequences of performing chronic exercise have not been sufficiently studied in contrast to the effects of acute bouts of exercise. The porpoise of this work was to determine the effect that a popular exercise regimen (chronic/moderate/aerobic exercise) has on the proportion of different immune cell subsets, their function and if it affects the cannabinoid system with potentially functional implications on the immune system. A marked increase in several immune cell subsets and their expression of cannabinoid receptors was expected, as well as an enhanced proliferative and cytotoxic activity by total splenocytes in exercised animals. For this study male Wistar rats performed treadmill running 5 times a week for a period of 10 weeks, at moderate intensity. Our results showed a significant decrease in lymphocyte subpopulations (CD4+, Tγδ, and CD45 RA+ cells) and an increase in the cannabinoid receptors expression in those same cell. Although functional assays did not reveal any variation in total immunoglobulin production or NK cells cytotoxic activity, proliferative capability of total splenocytes increased in trained rats. Our results further support the notion that exercise affects the immunological system and extends the description of underlying mechanisms mediating such effects. Altogether, our results contribute to the understanding of the benefits of exercise on the practitioner´s general health.

Intermittent ethanol exposure during adolescence impairs cannabinoid type 1 receptor-dependent long-term depression and recognition memory in adult mice.

Binge drinking is a significant problem in adolescent populations, and because of the reciprocal interactions between ethanol (EtOH) consumption and the endocannabinoid (eCB) system, we sought to determine if adolescent EtOH intake altered the localization and function of the cannabinoid 1 (CB1) receptors in the adult brain. Adolescent mice were exposed to a 4-day-per week drinking in the dark (DID) procedure for a total of 4 weeks and then tested after a 2-week withdrawal period. Field excitatory postsynaptic potentials (fEPSPs), evoked by medial perforant path (MPP) stimulation in the dentate gyrus molecular layer (DGML), were significantly smaller. Furthermore, unlike control animals, CB1 receptor activation did not depress fEPSPs in the EtOH-exposed animals. We also examined a form of excitatory long-term depression that is dependent on CB1 receptors (eCB-eLTD) and found that it was completely lacking in the animals that consumed EtOH during adolescence. Histological analyses indicated that adolescent EtOH intake significantly reduced the CB1 receptor distribution and proportion of immunopositive excitatory synaptic terminals in the medial DGML. Furthermore, there was decreased binding of [35S]guanosine-5*-O-(3-thiotriphosphate) ([35S] GTPγS) and the guanine nucleotide-binding (G) protein Gαi2 subunit in the EtOH-exposed animals. Associated with this, there was a significant increase in monoacylglycerol lipase (MAGL) mRNA and protein in the hippocampus of EtOH-exposed animals. Conversely, deficits in eCB-eLTD and recognition memory could be rescued by inhibiting MAGL with JZL184. These findings indicate that repeated exposure to EtOH during adolescence leads to long-term deficits in CB1 receptor expression, eCB-eLTD, and reduced recognition memory, but that these functional deficits can be restored by treatments that increase endogenous 2-arachidonoylglycerol.

Opposed cannabinoid 1 receptor (CB1R) expression in the prefrontal cortex vs. nucleus accumbens is associated with alcohol consumption in male rats

Abusive alcohol consumption is a health problem, worldwide. There is extensive literature indicating that cannabinoid 1 receptor (CB1R) plays a crucial role in mediating alcohol’s reward effects. Maternal care deprivation (MCD) is a reliable rodent model of early life stress that leads to high levels of anxiety and alterations in motivation, which may increase vulnerability to alcohol consumption. The present study researched whether anxiety-like behaviors and the level of motivation for a natural reward, and CB1R expression in the prefrontal cortex (PFC) and nucleus accumbens (NAcc) can predict alcohol consumption in non-MCD and MCD male rats. Results indicate that MCD increases anxiety-like behaviors, i.e., reduces time in open arms in the elevated plus maze and increases alcohol intake. In turn, the motivation for a palatable reward, i.e., a chocolate flavored pellet, was not affected by MCD. MCD reduces CB1R expression in the PFC and increases it in the NAcc. Hence, both higher anxiety-like behaviors and higher CB1R expression in the NAcc and lower CB1R expression in the PFC are associated with higher alcohol intake. These results suggest that early life adverse experiences induce a reprogramming of the brain’s endocannabinoid system that very likely contributes to making the brain vulnerable to develop alcohol abuse and dependence.

Enterocolic increase of cannabinoid receptor type 1 and type 2 and clinical improvement after probiotic administration in dogs with chronic signs of colonic dysmotility without mucosal inflammatory changes.

Colonic dysmotility in dogs can cause different GI signs. Sometimes, histology of enterocolic biopsies does not reveal inflammatory infiltrates or mucosal lesions that are typically associated with clinical disease activity. It is speculated that, similarly to humans, colonic dysmotility may be anxiety-based, although recent data demonstrate that irritable bowel syndrome (IBS) could result from acute infectious enteritis. Specific Lactobacillus spp. strains administered orally in humans induced the expression of μ-opioid and cannabinoid receptors in mucosal enterocytes, modulating intestinal morphine-like analgesic functions. We investigated the potential association of GI signs caused by colonic dysmotility and mucosal expression of cannabinoid receptors in intestinal epithelial cells and the number of mucosal mast cells. Ten to 15 endoscopic biopsies were collected from colonic mucosa of 20 dogs diagnosed with dysmotility disturbances before and after probiotic (Slab51 bacterial blend; Sivoy® ) administration (3-month period). Number and distribution of mast cells (MCs), and cannabinoid receptor type 1 (CB1) and type 2 (CB2) were evaluated by immunohistochemistry and PCR. Results were compared to data obtained from five clinically healthy dogs (archive samples). Decreased numbers of MCs (P<.0001) and increased CB1- and CB2-positive epithelial cells (P<.0001) in diseased dogs were positively associated with post-treatment CCECAI scores (P<.0001). Our results suggest that probiotic administration can reduce signs of colonic dysmotility, possibly due to microbiota modulation and epithelial cell receptor-mediated signaling in intestinal mucosa.

Involvement of Spinal Cannabinoid CB2 Receptors in Exercise-Induced Antinociception

Muscle pain affects approximately 11–24% of the global population. Several studies have shown that exercise is a non-pharmacological therapy to pain control. It has been suggested that the endocannabinoid system is involved in this antinociceptive effect. However, the participation of this pathway is unclear. The present study aimed to investigate whether spinal cannabinoid CB2 receptors participate in the exercise-induced antinociception. The inflammatory muscle pain model was induced by the intramuscular injection of carrageenan. Tactile allodynia and thermal hyperalgesia were determined with the von Frey filaments and hot-plate tests. C57BL/6J female mice underwent a swimming training protocol that lasted 3 weeks. This protocol of exercise reduced carrageenan-induced tactile allodynia and thermal hyperalgesia and this effect was prevented by the cannabinoid CB2 receptors inverse agonist AM630 and potentiated by MAFP (inhibitor of the enzyme that metabolizes endocannabinoids) and minocycline (microglia inhibitor). In addition, exercise increased the endocannabinoid anandamide levels and cannabinoid CB2 receptors expression whereas it reduced Iba1 (microglial marker) protein expression as well as pro-inflammatory cytokines (TNF-α and IL-1β) in the spinal cord of mice with inflammatory muscle pain. Swimming training also reduced muscle temperature of carrageen-treated animals. The present study suggests that activation of spinal cannabinoid CB2 receptors and reduction of activated microglia are involved in exercise-induced antinociception.

Cessation of fluoxetine treatment increases alcohol seeking during relapse and dysregulates endocannabinoid and glutamatergic signaling in the central amygdala.

Administration of selective serotonin reuptake inhibitors (SSRIs), typically used as antidepressants, induces long-lasting behavioral changes associated with alcohol use disorder (AUD). However, the contribution of SSRI (fluoxetine)-induced alterations in neurobiological processes underlying alcohol relapse such as endocannabinoid and glutamate signaling in the central amygdala (CeA) remains largely unknown. We utilized an integrative approach to study the effects of repeated fluoxetine administration during abstinence on ethanol drinking. Gene expression and biochemical and electrophysiological studies explored the hypothesis that dysregulation in glutamatergic and endocannabinoid mechanisms in the CeA underlie the susceptibility to alcohol relapse. Cessation of daily treatment with fluoxetine (10 mg/kg) during abstinence resulted in a marked increase in ethanol seeking during re-exposure periods. The increase in ethanol self-administration was associated with (a) reductions in levels of the endocannabinoids N-arachidonoylethanolomine and 2-arachidonoylglycerol in the CeA, (b) increased amygdalar gene expression of cannabinoid type-1 receptor (CB1), N-acyl phosphatidylethanolamine phospholipase D (Nape-pld), fatty acid amid hydrolase (Faah), (c) decreased amygdalar gene expression of ionotropic AMPA (GluA2 and GluA4) and metabotropic (mGlu3) glutamate receptors, and (d) increased glutamatergic receptor function. Overall, our data suggest that the administration of the antidepressant fluoxetine during abstinence dysregulates endocannabinoid signaling and glutamatergic receptor function in the amygdala, facts that likely facilitate alcohol drinking behavior during relapse.

Electroacupuncture-induced cannabinoid receptor expression in repair of abducens nerve

Objective: Through the development of beagle abducens nerve injury model, taking electroacupuncture as the core and microglia as the starting point, the author investigated whether electroacupuncture can promote the repair of injured abducens nerve by cannabinoid receptor-mediated regulation of microglia activation.Methods: Healthy beagle dogs were randomly divided into five groups: sham operation group (A), injury group (B), electroacupuncture pretreatment group (C), antagonist group (D) and solvent group (E). After stimulation with electroacupuncture, the expression of cannabinoid 1 receptor (CB1R) and cannabinoid 2 receptor (CB2R) in A, B and C microglia cells was detected by Western Bolt analysis, and further the expression of CB2R in five groups was further analyzed by immunofluorescence, thereby statistical differences were analyzed.Results: Among group A, group B and group C, Western Blot analysis showed that there were no significant changes in the expression of CB1R protein after electroacupuncture [F (2, 12)=1.75, p = 0.215]. After electroacupuncture preconditioning for 15 min for 2 weeks, group C was compared with group A and group B, which showed CB2 was affected. The expression of CB2R protein was significantly increased among groups A, B and C [F (2, 12)=5189.57, p < 0.001], but there was no significant difference in the expression of CB2R protein between group A and group B (p > 0.05). The results of immunofluorescence showed that Arginse/CD11b was significantly increased in group C comparing to group A (*p < 0.001), while there was a significant increase in group E comparing to group A about Arginse/CD11b [F (4, 20)=4345.44, p < 0.001].Conclusions: The CB2R in the cannabinoid receptor is mainly involved in the electro-acupuncture-induced neuroprotection. Electroacupuncture can promote the repair of injured abducens nerve by CB2R-mediated activation of microglia.

Cocaine-Induced Reinstatement of Cocaine Seeking Provokes Changes in the Endocannabinoid and N-Acylethanolamine Levels in Rat Brain Structures.

There is strong support for the role of the endocannabinoid system and the noncannabinoid lipid signaling molecules, N-acylethanolamines (NAEs), in cocaine reward and withdrawal. In the latest study, we investigated the changes in the levels of the above molecules and expression of cannabinoid receptors (CB1 and CB2) in several brain regions during cocaine-induced reinstatement in rats. By using intravenous cocaine self-administration and extinction procedures linked with yoked triad controls, we found that a priming dose of cocaine (10 mg/kg, i.p.) evoked an increase of the anadamide (AEA) level in the hippocampus and prefrontal cortex only in animals that had previously self-administered cocaine. In the same animals, the level of 2-arachidonoylglycerol (2-AG) increased in the hippocampus and nucleus accumbens. Moreover, the drug-induced relapse resulted in a potent increase in NAEs levels in the cortical areas and striatum and, at the same time, a decrease in the tissue levels of oleoylethanolamide (OEA) and palmitoylethanolamide (PEA) was noted in the nucleus accumbens, cerebellum, and/or hippocampus. At the level of cannabinoid receptors, a priming dose of cocaine evoked either upregulation of the CB1 and CB2 receptors in the prefrontal cortex and lateral septal nuclei or downregulation of the CB1 receptors in the ventral tegmental area. In the medial globus pallidus we observed the upregulation of the CB2 receptor only after yoked chronic cocaine treatment. Our findings support that in the rat brain, the endocannabinoid system and NAEs are involved in cocaine induced-reinstatement where these molecules changed in a region-specific manner and may represent brain molecular signatures for the development of new treatments for cocaine addiction.

Cannabinoid type-1 receptor blockade restores neurological phenotypes in two models for Down syndrome

Intellectual disability is the most limiting hallmark of Down syndrome, for which there is no gold-standard clinical treatment yet. The endocannabinoid system is a widespread neuromodulatory system involved in multiple functions including learning and memory processes. Alterations of this system contribute to the pathogenesis of several neurological and neurodevelopmental disorders. However, the involvement of the endocannabinoid system in the pathogenesis of Down syndrome has not been explored before. We used the best-characterized preclinical model of Down syndrome, the segmentally trisomic Ts65Dn model. In male Ts65Dn mice, cannabinoid type-1 receptor (CB1R) expression was enhanced and its function increased in hippocampal excitatory terminals. Knockdown of CB1R in the hippocampus of male Ts65Dn mice restored hippocampal-dependent memory. Concomitant with this result, pharmacological inhibition of CB1R restored memory deficits, hippocampal synaptic plasticity and adult neurogenesis in the subgranular zone of the dentate gyrus. Notably, the blockade of CB1R also normalized hippocampal-dependent memory in female Ts65Dn mice. To further investigate the mechanisms involved, we used a second transgenic mouse model overexpressing a single gene candidate for Down syndrome cognitive phenotypes, the dual specificity tyrosine-phosphorylation-regulated kinase 1A (DYRK1A). CB1R pharmacological blockade similarly improved cognitive performance, synaptic plasticity and neurogenesis in transgenic male Dyrk1A mice. Our results identify CB1R as a novel druggable target potentially relevant for the improvement of cognitive deficits associated with Down syndrome.

Decreased Expression of Cannabinoid Receptors in the Eutopic and Ectopic Endometrium of Patients with Adenomyosis.

Objective Adenomyosis is a common gynecologic benign disease that may have a life-long negative impact on women. Previous studies have indicated that the endocannabinoid system may participate in the progress of endometriosis. Our research aims to analyze the expression patterns of the typical cannabinoid receptors (CB1 and CB2), the main constituents of the endocannabinoid system, in endometrial samples derived from patients diagnosed as adenomyosis or not. Methods Eutopic and corresponding ectopic endometrium from 45 premenopausal women diagnosed as adenomyosis and normal endometrium from 34 age-matched women lacking evidence of adenomyosis were examined by immunohistochemistry and quantitative real-time polymerase chain reaction (qRT-PCR) to determine the CB1 and CB2 expression levels. Results In either the proliferative or the secretory phase, CB1 and CB2 protein and mRNA levels were both significantly lower in the eutopic and ectopic endometrium of adenomyosis when compared with normal endometrium. For women with adenomyosis, CB1 and CB2 protein and mRNA levels were much lower in the ectopic endometrium than the eutopic in both phases of the cycle. Both CB1 and CB2 protein and mRNA levels were increased during the secretory phase in normal endometrium, while CB1 lost its cyclic variation in the eutopic and ectopic endometrium from patients diagnosed as adenomyosis. Conclusion The decreased expression of CB1 and CB2 in the eutopic and ectopic endometrium from patients diagnosed as adenomyosis suggests that cannabinoid receptors may participate in the pathogenesis of adenomyosis.

Systemic administration of serotonin exacerbates abdominal pain and colitis via interaction with the endocannabinoid system

Background and aimsMolecular basis of abdominal pain in IBD is not fully characterized. Serotonin (5-HT) increases visceral pain severity and contributes to exacerbation of inflammation. Moreover, it is well established that decreased anandamide (AEA) signaling in the gut increases visceral pain severity. The aim of this study was to investigate the interplay between 5-HT and endocannabinoid signaling in colitis. MethodsWe used 3% DSS in drinking water to induce colitis in mice. From day 3 5-HT was administered for 5 days and each day visceromotor response to colorectal distention (CRD) was measured. Expression of cannabinoid (CB) receptors as well as enzymes responsible of biosynthesis and degradation of endocannabinoids were investigated. Moreover, endocannabinoid levels were assessed by mass spectrometry. Additionally, we measured the expression of enzymes synthesizing 5-HT and AEA in the colon of IBD patients and healthy controls. ResultsChronic exposure to 5-HT increased visceromotor response to CRD and worsened colitis, which was associated with decrease of AEA via 5-HT3 and 5-HT4 receptors. Moreover, exposure to 5-HT led to the downregulation of CB1 receptors. Colonic levels of N-acyl-phosphatidylethanolamine-specific phospholipase D (NAPE-PLD), which is responsible for synthesis of AEA, significantly declined after chronic treatment with 5-HT and this effect was reversed by the 5-HT3 and 5-HT4 receptor antagonists. NAPE-PLD was also downregulated in the colon of UC patients. ConclusionsOur study shows a link between 5-HT and endocannabinoid signaling pathways in IBD. Thus, pharmacological blockade of 5-HT signaling or supplementation with endocannabinoids in the gut might be of benefit in severe cases of abdominal pain in IBD.