Tag Archives: CNR1

Cannabinoid Receptor 1 (CNR1) Gene Variant Moderates Neural Index of Cognitive Disruption during Nicotine Withdrawal.

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“Nicotine withdrawal-related disruption of cognitive control may contribute to the reinforcement of tobacco use.

Identification of gene variants that predict this withdrawal phenotype may lead to tailored pharmacotherapy for smoking cessation.

Variation on the cannabinoid receptor 1 gene (CNR1) has been related to nicotine dependence, and CNR1 antagonists may increase attention and memory functioning.

The current findings suggest potential efficacy of cannabinoid RECEPTOR antagonism as a pharmacotherapy approach for smoking cessation among individuals who exhibit greater nicotine withdrawal-related cognitive disruption.”

http://www.ncbi.nlm.nih.gov/pubmed/27453054

Mechanical and material properties of cortical and trabecular bone from cannabinoid receptor-1-null (Cnr1-/-) mice.

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“The endocannabinoid system is known for its regulatory effects on bone metabolism through the cannabinoid receptors, Cnr1 and Cnr2. In this study we analysed the mechanical and material properties of long bones from Cnr1-/- mice on a C57BL/6 background. Tibiae and femora from 5- and 12-week-old mice were subjected to three-point bending to measure bending stiffness and yield strength. Elastic modulus, density and mineral content were measured in the diaphysis. Second moment of area (MOA2), inner and outer perimeters of the cortical shaft and trabecular fractional bone volume (BV/TV) were measured using micro-CT. In Cnr1-/- males and females at both ages the bending stiffness was reduced due to a smaller MOA2. Bone from Cnr1-/- females had a greater modulus than wild-type controls, although no differences were observed in males. BV/TV of 12-week-old Cnr1-/- females was greater than controls, although no difference was seen at 5-weeks. On the contrary, Cnr1-/- males had the same BV/TV as controls at 12-weeks while they had significantly lower values at 5-weeks. This study shows that deleting Cnr1 decreases the amount of cortical bone in both males and females at 12-weeks, but increases the amount of trabecular bone only in females.”

http://www.ncbi.nlm.nih.gov/pubmed/27401043

Autophagy activation by novel inducers prevents BECN2-mediated drug tolerance to cannabinoids.

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“Cannabinoids and related drugs generate profound behavioral effects (such as analgesic effects) through activating CNR1 (cannabinoid receptor 1 [brain]). However, repeated cannabinoid administration triggers lysosomal degradation of the receptor and rapid development of drug tolerance, limiting the medical use of marijuana in chronic diseases.

Here we show that a protein involved in macroautophagy/autophagy (a conserved lysosomal degradation pathway), BECN2 (beclin 2), mediates cannabinoid tolerance by preventing CNR1 recycling and resensitization after prolonged agonist exposure, and deletion of Becn2 rescues CNR1 activity in mouse brain and conveys resistance to analgesic tolerance to chronic cannabinoids.

Overall, our findings demonstrate the functional link among autophagy, receptor signaling and animal behavior regulated by psychoactive drugs, and develop a new strategy to prevent tolerance and improve medical efficacy of cannabinoids by modulating the BECN2 interactome and autophagy activity.”

http://www.ncbi.nlm.nih.gov/pubmed/27305347

Cannabinoid Receptors Are Overexpressed in CLL but of Limited Potential for Therapeutic Exploitation.

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“The cannabinoid receptors 1 and 2 (CNR1&2) are overexpressed in a variety of malignant diseases and cannabinoids can have noteworthy impact on tumor cell viability and tumor growth.

Patients diagnosed with chronic lymphocytic leukemia (CLL) present with very heterogeneous disease characteristics translating into highly differential risk properties.

To meet the urgent need for refinement in risk stratification at diagnosis and the search for novel therapies we studied CNR expression and response to cannabinoid treatment in CLL.

Expression levels of CNR1&2 were determined in 107 CLL patients by real-time PCR and analyzed with regard to prognostic markers and survival.

In contrast to other tumor entities, our data suggest a limited usability of cannabinoids for CLL therapy. Nonetheless, we could define CNR1 mRNA expression as novel prognostic marker.”

http://www.ncbi.nlm.nih.gov/pubmed/27248492

Getting into the weed: the role of the endocannabinoid system in the brain-gut axis.

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“The actions of cannabis are mediated by receptors that are part of an endogenous cannabinoid system.

The endocannabinoid system (ECS) consists of the naturally occurring ligands N-arachidonoylethanolamine (anandamide) and 2-arachidonoylglycerol (2-AG), their biosynthetic and degradative enzymes, and the cannabinoid receptors CB1 and CB2.

The ECS is a widely distributed transmitter system that controls gut functions peripherally and centrally. It is an important physiologic regulator of gastrointestinal motility.

Polymorphisms in the gene encoding CB1 (CNR1) have been associated with some forms of irritable bowel syndrome. The ECS is involved in the control of nausea and vomiting and visceral sensation. The homeostatic role of the ECS also extends to the control of intestinal inflammation.

We review the mechanisms by which the ECS links stress and visceral pain. CB1 in sensory ganglia controls visceral sensation, and transcription of CNR1 is modified through epigenetic processes under conditions of chronic stress. These processes might link stress with abdominal pain.

The ECS is also involved centrally in the manifestation of stress, and endocannabinoid signaling reduces the activity of hypothalamic-pituitary-adrenal pathways via actions in specific brain regions-notably the prefrontal cortex, amygdala, and hypothalamus.

Agents that modulate the ECS are in early stages of development for treatment of gastrointestinal diseases. Increasing our understanding of the ECS will greatly advance our knowledge of interactions between the brain and gut and could lead to new treatments for gastrointestinal disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/27133395

Cannabinoid receptor signaling regulates liver development and metabolism.

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“Endocannabinoid (EC) signaling mediates psychotropic effects and regulates appetite.

By contrast, potential roles in organ development and embryonic energy consumption remain unknown. Here, we demonstrate that genetic or chemical inhibition of cannabinoid receptor (Cnr) activity disrupts liver development and metabolic function in zebrafish (Danio rerio), impacting hepatic differentiation, but not endodermal specification: loss of cannabinoid receptor 1 (cnr1) and cnr2 activity leads to smaller livers with fewer hepatocytes, reduced liver-specific gene expression and proliferation.

Our work describes a novel developmental role for EC signaling, whereby Cnr-mediated regulation of Srebfs and methionine metabolism impacts liver development and function.”

http://www.ncbi.nlm.nih.gov/pubmed/26884397

Effects of chronic exercise on the endocannabinoid system in Wistar rats with high-fat diet-induced obesity.

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“The endocannabinoid system is dysregulated during obesity in tissues involved in the control of food intake and energy metabolism.

We examined the effect of chronic exercise on the tissue levels of endocannabinoids (eCBs) and on the expression of genes coding for cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2) (Cnr1 and Cnr2, respectively) in the subcutaneous (SAT) and visceral adipose tissues and in the soleus and extensor digitorim longus (EDL) muscles, in rats fed with standard or high-fat diet…

The levels of eCBs and Cnr1 expression are altered in a tissue-specific manner following a high-fat diet, and chronic exercise reverses some of these alterations.”

http://www.ncbi.nlm.nih.gov/pubmed/26880264

Elucidating Cannabinoid Biology in Zebrafish (Danio rerio).

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“Although exogenous cannabinoids, like those contained in marijuana, are known to exert their effects by disrupting the endocannabinoid system, a dearth of knowledge exists about the potential toxicological consequences on public health.

Conversely, the endocannabinoid system represents a promising therapeutic target for a plethora of disorders because it functions to endogenously regulate a vast repertoire of physiological functions.

Accordingly, the rapidly expanding field of cannabinoid biology has sought to leverage model organisms in order to provide both toxicological and therapeutic insights about altered endocannabinoid signaling.

The primary goal of this manuscript is to review the existing field of cannabinoid research in the genetically tractable zebrafish model-focusing on the cannabinoid receptor genes, cnr1 and cnr2, and the genes that produce enzymes for synthesis and degradation of the cognate ligands anandamide and 2-arachidonylglycerol.

Consideration is also given to research that has studied the effects of exposure to exogenous phytocannabinoids and synthetic cannabinoids that are known to interact with cannabinoid receptors.

These results are considered in the context of either endocannabinoid gene expression or endocannabinoid gene function, and are integrated with findings from rodent studies.

This provides the framework for a discussion of how zebrafish may be leveraged in the future to provide novel toxicological and therapeutic insights in the field of cannabinoid biology, which has become increasingly significant given recent trends in cannabis legislation.”

http://www.ncbi.nlm.nih.gov/pubmed/26192460

Association between cannabinoid receptor gene (CNR1) and childhood attention deficit/hyperactivity disorder in Spanish male alcoholic patients

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“The CB1 receptor is encoded by the CNR1 gene (6q14–q15), which is known to carry a nine-allele microsatellite polymorphism containing repeats of a single trinucleotide, ATT, which localizes to the 3’UTR of the gene and has been related to drug dependency states in Caucasian populations.

Moreover, a link has been found between this polymorphism and the properties of the event-related wave p300, some studies having suggested that p300 variations might function as a marker for an underlying, hereditary, predisposition to alcoholism.

Moreover, a direct relationship has been found between p300 wave fluctuations and attention deficit/hyperactivity disorder (ADHD). In recent years, the relationship between ADHD and addictions has been stressed. ADHD has been linked to the malfunctioning of catecholaminergic systems, which also play a fundamental role in the brain’s rewarding system.

These data suggest that the link between the cannabinoid system and the p300 wave could be related to some aspects of ADHD.

In this study, we found a quantitative relationship between the largest-sized alleles of the CNR1 gene and the presence of ADHD during childhood in Spanish male alcoholic patients…

To the best of our knowledge, this is the first study relating the CNR1-gene polymorphisms with ADHD in alcoholic patients.

These data are consistent with the fact that the cannabinoid system is known to affect dopaminergic transmission, with the malfunctioning of the dopaminergic system being regarded as a potential physiopathological cause of ADHD. Further studies are needed to determine the functional basis of the observed association.”

http://www.nature.com/mp/journal/v8/n5/full/4001278a.html

Association of the cannabinoid receptor gene (CNR1) with ADHD and post-traumatic stress disorder.

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“Attention deficit hyperactivity disorder (ADHD) is a highly heritable disorder affecting some 5-10% of children and 4-5% of adults. The cannabinoidreceptor gene (CNR1) is a positional candidate gene due to its location near an identified ADHD linkage peak on chromosome 6, its role in stress and dopamine regulation, its association with other psychiatric disorders that co-occur with ADHD, and its function in learning and memory.

…the CNR1 gene may be a risk factor forADHD and possibly PTSD, and that this gene warrants further investigation for a role in neuropsychiatric disorders.

These data provide support for a putative role of endogenous cannabinoids in ADHD, and PTSD.

The CNR1gene may contribute to shared underlying risk continua, such as emotional dysregulation in response to stress, across these diverse diagnostic groups. Increased amygdala activity, poor stress reactivity as reflected by HPA response, and poor prefrontal cortical modulation is a plausible underlying mechanism of liability that may be shared across disorders.

Taken together with the current findings, we suggest that this gene may be an important risk variant in the emotional regulation difficulties underlying ADHD, PTSD, and possibly other co-morbid conditions (such as mood disorder); however, the role of CNR1 is likely small, particularly at the level of psychiatric diagnosis, so future work using more refined phenotypes or endophenotypes of affect regulation are necessary.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2685476/