Category Archives: Endocannabinoid System

Cannabinoid Receptor Interacting Protein (CRIP1a) suppresses agonist-driven CB1 receptor internalization, and regulates receptor replenishment in an agonist-biased manner.

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“Cannabinoid Receptor Interacting Protein1a (CRIP1a) is a CB1 receptor (CB1 R) distal C-terminus-associated protein that modulates CB1 R signaling via G proteins, and CB1 R down-regulation but not desensitization.

In the present study, we determined the involvement of CRIP1a in CB1 R plasma membrane trafficking.

These studies demonstrate a novel role for CRIP1a in agonist-driven CB1 R cell surface regulation postulated to occur by two mechanisms: attenuating agonist-mediated but not internalization in the absence of exogenous agonists, and biased agonist-dependent trafficking of de novo synthesized receptor to the cell surface.”

http://www.ncbi.nlm.nih.gov/pubmed/27513693

Opposite Cannabis-Cognition Associations in Psychotic Patients Depending on Family History.

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“The objective of this study is to investigate cognitive performance in a first-episode psychosis sample, when stratifying the interaction by cannabis use and familial or non-familial psychosis.

We found that cannabis use was associated with worse working memory, regardless of family history. However, cannabis use was clearly associated with worse cognitive performance in patients with no family history of psychosis, in cognitive domains including verbal memory, executive function and global cognitive index, whereas cannabis users with a family history of psychosis performed better in these domains.

The main finding of the study is that there is an interaction between cannabis use and a family history of psychosis in the areas of verbal memory, executive function and global cognition: that is, cannabis use is associated with a better performance in patients with a family history of psychosis and a worse performance in those with no family history of psychosis.

In order to confirm this hypothesis, future research should explore the actual expression of the endocannabinoid system in patients with and without a family history of psychosis.”

http://www.ncbi.nlm.nih.gov/pubmed/27513670

Synthesis and Biological Evaluation of Thiophene-Based Cannabinoid Receptor Type 2 Radiotracers for PET Imaging.

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“Over the past two decades, our understanding of the endocannabinoid system has greatly improved due to the wealth of results obtained from exploratory studies. Currently, two cannabinoid receptor subtypes have been well-characterized. The cannabinoid receptor type 1 (CB1) is widely expressed in the central nervous system, while the levels of the cannabinoid receptor type 2 (CB2) in the brain and spinal cord of healthy individuals are relatively low.”

http://www.ncbi.nlm.nih.gov/pubmed/27512365

Cross-validated stable-isotope dilution GC-MS and LC-MS/MS assays for monoacylglycerol lipase (MAGL) activity by measuring arachidonic acid released from the endocannabinoid 2-arachidonoyl glycerol.

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“2-Arachidonoyl glycerol (2AG) is an endocannabinoid that activates cannabinoid (CB) receptors CB1 and CB2. Monoacylglycerol lipase (MAGL) inactivates 2AG through hydrolysis to arachidonic acid (AA) and glycerol, thus modulating the activity at CB receptors.” http://www.ncbi.nlm.nih.gov/pubmed/27511795

Acute Stress Suppresses Synaptic Inhibition and Increases Anxiety via Endocannabinoid Release in the Basolateral Amygdala.

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“Stress and glucocorticoids stimulate the rapid mobilization of endocannabinoids in the basolateral amygdala (BLA).

Cannabinoid receptors in the BLA contribute to anxiogenesis and fear-memory formation. We tested for rapid glucocorticoid-induced endocannabinoid regulation of synaptic inhibition in the rat BLA.

Together, these findings suggest that acute stress causes a long-lasting suppression of synaptic inhibition in BLA neurons via a membrane glucocorticoid receptor-induced release of 2-AG at GABA synapses, which contributes to stress-induced anxiogenesis.

We show that acute stress increases anxiety-like behavior via an endocannabinoid-dependent mechanism centered in the BLA.

The stress-induced endocannabinoid modulation of synaptic transmission in the BLA contributes, therefore, to the stress regulation of anxiety, and may play a role in anxiety disorders of the amygdala.”

http://www.ncbi.nlm.nih.gov/pubmed/27511017

Medical Marijuana-Opportunities and Challenges

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“Over the recent years, public and political opinions have demonstrated increasing support for the legalization of medical marijuana.

To date, 24 states as well as the District of Columbia have legalized cannabis for medical use, 4 states have legalized the recreational use of Marijuana.

Marijuana is derived from the hemp plant Cannabis sativa. Δ-9-tetrahydrocannabinol (THC) is the major psychoactive constituent of cannabis, while cannabidiol (CBD) is the major non-psychoactive constituent. THC is a partial agonist at CB1 and CB2 receptors, while CBD at high levels is an antagonist CB1 and CB2.

CB1 is abundantly expressed in the brain, and CB2 is expressed on immune cells (expression of CB2 on neurons remains controversial). The brain also produces endogenous cannabis-like substances (endocannabinoids) that bind and activate the CB1/CB2 receptors.

There is tremendous interest in harnessing the therapeutic potential of plant-derived and synthetic cannabinoids.

This Editorial provides an overview of diseases that may be treated by cannabinoids.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4948749/

Cannabinoids As Potential Treatment for Chemotherapy-Induced Nausea and Vomiting.

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“Despite the advent of classic anti-emetics, chemotherapy-induced nausea is still problematic, with vomiting being somewhat better managed in the clinic.

If post-treatment nausea and vomiting are not properly controlled, anticipatory nausea-a conditioned response to the contextual cues associated with illness-inducing chemotherapy-can develop. Once it develops, anticipatory nausea is refractive to current anti-emetics, highlighting the need for alternative treatment options.

One of the first documented medicinal uses of Δ(9)-tetrahydrocannabinol (Δ(9)-THC) was for the treatment of chemotherapy-induced nausea and vomiting (CINV), and recent evidence is accumulating to suggest a role for the endocannabinoid system in modulating CINV.

Here, we review studies assessing the therapeutic potential of cannabinoids and manipulations of the endocannabinoid system in human patients and pre-clinical animal models of nausea and vomiting.”

http://www.ncbi.nlm.nih.gov/pubmed/27507945

The Effect of Muscarinic Receptor Modulators on the Antinociception Induced by CB2 Receptor Agonist, JWH133 in Mice.

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“There is no published study regarding the interaction between muscarinic receptor modulators and antinociception induced by cannabinoidreceptor (CB2) agonist. The effect of pilocarpine (a muscarinic agonist) and atropine (a muscarinic antagonist) on JWH-133 (a CB2 agonist) induced analgesia in mice was studied. First the analgesic effect of JWH-133 (0.001-1 mg/Kg) or pilocarpine (2.5-20 mg/kg) or atropine (0.2-5 mg/kg) was evaluated. Subsequently, the effect of co-administration of pilocarpine (2.5 mg/kg) or atropine (5 mg/kg) and JWH-133 (0.001-1 mg/Kg) were studied too. JWH-133 and pilocarpine provoked antinociception in mice but atropine did not. Pilocarpine potentiated the analgesic effect of JWH-133 but atropine antagonized that. It can be concluded that JWH-133 induced antinociception is affected by muscarinic receptor modulators in mice.”

http://www.ncbi.nlm.nih.gov/pubmed/27504865

Endocannabinoid signaling enhances visual responses through modulation of intracellular chloride levels in retinal ganglion cells.

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“Type 1 cannabinoid receptors (CB1Rs) are widely expressed in the vertebrate retina but the role of endocannabinoids in vision is not fully understood. Here we identified a novel mechanism underlying a CB1R-mediated increase in retinal ganglion cell (RGC) intrinsic excitability acting through AMPK-dependent inhibition of NKCC1 activity.

Clomeleon imaging and patch clamp recordings revealed that inhibition of NKCC1 downstream of CB1R activation reduces intracellular Cl– levels in RGCs, hyperpolarizing the resting membrane potential. We confirmed that such hyperpolarization enhances RGC action potential firing in response to subsequent depolarization, consistent with the increased intrinsic excitability of RGCs observed with CB1R activation.

Using a dot avoidance assay in freely swimming Xenopus tadpoles we demonstrate that CB1R activation markedly improves visual contrast sensitivity under low light conditions.

These results highlight a role for endocannabinoids in vision, and present a novel mechanism for cannabinoid modulation of neuronal activity through Cl– regulation.”

http://www.ncbi.nlm.nih.gov/pubmed/27501334

Mice Expressing a “Hyper-Sensitive” Form of the Cannabinoid Receptor 1 (CB1) Are Neither Obese Nor Diabetic.

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“Multiple lines of evidence implicate the endocannabinoid signaling system in the modulation of metabolic disease.

Genetic or pharmacological inactivation of CB1 in rodents leads to reduced body weight, resistance to diet-induced obesity, decreased intake of highly palatable food, and increased energy expenditure.

Cannabinoid agonists stimulate feeding in rodents and increased levels of endocannabinoids can disrupt lipid metabolism. Therefore, the hypothesis that sustained endocannabinoid signaling can lead to obesity and diabetes was examined in this study using S426A/S430A mutant mice expressing a desensitization-resistant CB1 receptor.

These mice display exaggerated and prolonged responses to acute administration of phytocannabinoids, synthetic cannabinoids, and endocannabinoids. As a consequence these mice represent a novel model for determining the effect of enhanced endocannabinoid signaling on metabolic disease.

Our results indicate that S426A/S430A mutant mice expressing the desensitization-resistant form of CB1 do not exhibit differences in body weight, food intake, glucose homeostasis, or re-feeding following a fast.”

http://www.ncbi.nlm.nih.gov/pubmed/27501235