Category Archives: Endocannabinoid System

The effects of cannabinoids on the endocrine system.

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“Cannabinoids are the derivatives of the cannabis plant, the most potent bioactive component of which is tetrahydrocannabinol (THC). The most commonly used drugs containing cannabinoids are marijuana, hashish, and hashish oil.

These compounds exert their effects via interaction with the cannabinoid receptors CB1 and CB2. Type 1 receptors (CB1) are localised mostly in the central nervous system and in the adipose tissue and many visceral organs, including most endocrine organs. Type 2 cannabinoid receptors (CB2) are positioned in the peripheral nervous system (peripheral nerve endings) and on the surface of the immune system cells.

Recently, more and more attention has been paid to the role that endogenous ligands play for these receptors, as well as to the role of the receptors themselves. So far, endogenous cannabinoids have been confirmed to participate in the regulation of food intake and energy homeostasis of the body, and have a significant impact on the endocrine system, including the activity of the pituitary gland, adrenal cortex, thyroid gland, pancreas, and gonads.

Interrelations between the endocannabinoid system and the activity of the endocrine system may be a therapeutic target for a number of drugs that have been proved effective in the treatment of infertility, obesity, diabetes, and even prevention of diseases associated with the cardiovascular system.”

 https://www.ncbi.nlm.nih.gov/pubmed/30618031
https://journals.viamedica.pl/endokrynologia_polska/article/view/58487

Cannabinoids-induced peripheral analgesia depends on activation of BK channels.

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 Brain Research“The endogenous cannabinoid system is involved in the physiological inhibitory control of pain and is of particular interest for the development of therapeutic approaches for pain management.

Selective activation of the peripheral CB1 cannabinoid receptor has been shown to suppress the heightened firing of primary afferents, which is the peripheral mechanism underlying neuropathic pain after nerve injury. However, the mechanism underlying this effect of CB1 receptor remains unclear.

The large-conductance calcium-activated potassium (BK) channels have been reported to participate in anticonvulsant and vasorelaxant effects of cannabinoids. We asked whether BK channels participate in cannabinoids-induced analgesia and firing-suppressing effects in primary afferents after nerve injury.

Here, using mice with chronic constriction injury(CCI)-induced neuropathic pain, antinociception action and firing-suppressing effect of HU210 were measured before and after BK channel blocker application. We found that local peripheral application of HU210 alleviated CCI-induced pain behavior and suppressed the heightened firing of injured fibers. Co-administration of IBTX with HU210 significantly reversed the analgesia and the firing-suppressing effect of HU210.

This result indicated that the peripheral analgesic effects of cannabinoids depends on activation of BK channels.”

https://www.ncbi.nlm.nih.gov/pubmed/30615887

https://www.sciencedirect.com/science/article/pii/S0006899319300071?via%3Dihub

Progress in Brain Cannabinoid CB2 Receptor Research: From Genes to Behavior.

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Neuroscience & Biobehavioral Reviews

“The type 2 cannabinoid receptor (CB2R) was initially regarded as a peripheral cannabinoid receptor. However, recent technological advances in gene detection, alongside the availability of transgenic mouse lines, indicate that CB2Rs are expressed in both neurons and glial cells in the brain under physiological and pathological conditions, and are involved in multiple functions at cellular and behavioral levels. Brain CB2Rs are inducible and neuroprotective via up-regulation in response to various insults, but display species differences in gene and receptor structures, CB2R expression, and receptor responses to various CB2R ligands. CB2R transcripts also differ between the brain and spleen. In the brain, CB2A is the major transcript isoform, while CB2A and CB2B transcripts are present at higher levels in the spleen. These new findings regarding brain versus spleen CB2R isoforms may in part explain why early studies failed to detect brain CB2R gene expression. Here, we review evidence supporting the expression and function of brain CB2R from gene and receptor levels to cellular functioning, neural circuitry, and animal behavior.”

https://www.ncbi.nlm.nih.gov/pubmed/30611802

https://www.sciencedirect.com/science/article/pii/S0149763418308297?via%3Dihub

Adenosine A2A-Cannabinoid CB1 Receptor Heteromers in the Hippocampus: Cannabidiol Blunts Δ9-Tetrahydrocannabinol-Induced Cognitive Impairment

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“At present, clinical interest in the plant-derived cannabinoid compound cannabidiol (CBD) is rising exponentially, since it displays multiple therapeutic properties. In addition, CBD can counteract the undesirable effects of the psychoactive cannabinoid Δ9-tetrahydrocannabinol (Δ9-THC) that hinder clinical development of cannabis-based therapies. Here, by combining in vivo and complementary molecular techniques, we demonstrate for the first time that CBD blunts the Δ9-THC-induced cognitive impairment in an adenosine A2A receptor (A2AR)-dependent manner. Overall, these data provide new evidence regarding the mechanisms of action of CBD and the nature of A2AR-CB1R interactions in the brain.”

https://www.ncbi.nlm.nih.gov/pubmed/30610611

https://link.springer.com/article/10.1007%2Fs12035-018-1456-3

Cannabinoid Receptor Type 1 Agonist ACEA Improves Cognitive Deficit on STZ-Induced Neurotoxicity Through Apoptosis Pathway and NO Modulation.

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“The cannabinoid system has the ability to modulate cellular and molecular mechanisms, including excitotoxicity, oxidative stress, apoptosis, and inflammation, acting as a neuroprotective agent, by its relationship with signaling pathways associated to the control of cell proliferation, differentiation, and survival. Recent reports have raised new perspectives on the possible role of cannabinoid system in neurodegenerative diseases like Alzheimer disease’s (AD).

Our study has demonstrated a participation of the cannabinoid system in cellular survival, involving the CB1 receptor, which occurs by positive regulation of the anti-apoptotic proteins, suggesting the participation of this system in neurodegenerative processes. Our data suggest that the cannabinoid system is an interesting therapeutic target for the treatment of neurodegenerative diseases.”

https://www.ncbi.nlm.nih.gov/pubmed/30607903

https://link.springer.com/article/10.1007%2Fs12640-018-9991-2

Multiple endocannabinoid-mediated mechanisms in the regulation of energy homeostasis in brain and peripheral tissues.

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“The endocannabinoid (eCB) system is widely expressed in many central and peripheral tissues, and is involved in a plethora of physiological processes. Among these, activity of the eCB system promotes energy intake and storage, which, however, under pathophysiological conditions, can favour the development of obesity and obesity-related disorders. It is proposed that eCB signalling is evolutionary beneficial for survival under periods of scarce food resources. Remarkably, eCB signalling is increased both in hunger and in overnutrition conditions, such as obesity and type-2 diabetes. This apparent paradox suggests a role of the eCB system both at initiation and at clinical endpoint of obesity. This review will focus on recent findings about the role of the eCB system controlling whole-body metabolism in mice that are genetically modified selectively in different cell types. The current data in fact support the notion that eCB signalling is not only engaged in the development but also in the maintenance of obesity, whereby specific cell types in central and peripheral tissues are key sites in regulating the entire body’s energy homeostasis.”

https://www.ncbi.nlm.nih.gov/pubmed/30599065

https://link.springer.com/article/10.1007%2Fs00018-018-2994-6

Theoretical Explanation for Reduced Body Mass Index and Obesity Rates in Cannabis Users

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“Obesity is treatment-resistant, and is linked with a number of serious, chronic diseases. Adult obesity rates in the United States have tripled since the early 1960s.

Recent reviews show that an increased ratio of omega-6 to omega-3 fatty acids contributes to obesity rates by increasing levels of the endocannabinoid signals AEA and 2-AG, overstimulating CB1R and leading to increased caloric intake, reduced metabolic rates, and weight gain.

Cannabis, or THC, also stimulates CB1R and increases caloric intake during acute exposures.

The present meta-analysis reveals significantly reduced body mass index and rates of obesity in Cannabis users, in conjunction with increased caloric intake.

We provide for the first time a causative explanation for this paradox, in which rapid and long-lasting downregulation of CB1R following acute Cannabis consumption reduces energy storage and increases metabolic rates, thus reversing the impact on body mass index of elevated dietary omega-6/omega-3 ratios.

Evidence suggests that, in the United States, many people may actually achieve net health benefits from moderate Cannabis use, due to reduced risk of obesity and associated diseases.”

https://www.liebertpub.com/doi/10.1089/can.2018.0045?_ga=2.221453528.1791159238.1546024140-1083808004.1546024140

“Reduced Body Mass Index and Obesity Rates in Cannabis Users”  https://www.genengnews.com/insights/reduced-body-mass-index-and-obesity-rates-in-cannabis-users/?fbclid=IwAR3a0wbfGoPwAR-pYQGCeLz-KYUFdiLJoj6Ja7rTTNGBYwkjIGw1fUjf5LI

 

n-3 polyunsaturated N-acylethanolamines are CB2 cannabinoid receptor-preferring endocannabinoids

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 Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids“Anandamide, the first identified endogenous cannabinoid and TRPV1 agonist, is one of a series of endogenous N-acylethanolamines, NAEs. We have generated novel assays to quantify the levels of multiple NAEs in biological tissues and their rates of hydrolysis through fatty acid amide hydrolase. This range of NAEs was also tested in rapid response assays of CB1, CB2 cannabinoid and TRPV1 receptors. The data indicate that PEA, SEA and OEA are not endocannabinoids or endovanilloids, and that the higher endogenous levels of these metabolites compared to polyunsaturated analogues are a correlate of their slow rates of hydrolysis. The n-6 NAEs (AEA, docosatetraenoyl and docosapentaenoyl derivatives) activated both CB1 and CB2 receptors, as well as TRPV1 channels, suggesting them to be ‘genuine’ endocannabinoids and ‘endovanilloids’. The n-3 NAEs (eicosapentaenoyl, docosapentaenoyl and docosahexaenoyl derivatives) activated CB2 receptors and some n-3 NAEs (docosapentaenoyl and docosahexaenoyl derivatives) also activated TRPV1 channels, but failed to activate the CB1 receptor. We hypothesise that the preferential activation of CB2 receptors by n-3 PUFA NAEs contributes, at least in some part, to their broad anti-inflammatory profile.”

https://www.ncbi.nlm.nih.gov/pubmed/30591150

https://www.sciencedirect.com/science/article/pii/S1388198118302026?via%3Dihub

Bidirectional modulation of food habit expression by the endocannabinoid system.

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European Journal of Neuroscience banner

“The compulsive, habitual behaviors that have been observed in individuals diagnosed with substance use disorders may be due to disruptions in the neural circuits that mediate goal-directed actions.

The endocannabinoid system has been shown to play a critical role in habit learning, but the role of this neuromodulatory system in habit expression is unclear.

Here, we investigated the role of the endocannabinoid system in established habitual actions using contingency degradation in male C57BL/6 mice.

We found that administration of the endocannabinoid transport inhibitor AM404 reduced habitual responding for food and that antagonism of cannabinoid receptor type 1 (CB1), but not transient receptor potential cation subfamily V (TRPV1), receptors produced a similar reduction in habitual responding.

Moreover, pharmacological stimulation of CB1 receptors increased habitual responding for food. Co-administration of an enzyme inhibitor that selectively increases the endocannabinoid 2-arachidonoyl glycerol (2-AG) with AM404 partially restored habitual responding for food.

Together, these findings demonstrate an important role for the endocannabinoid system in the expression of habits and provide novel insights into potential pharmacological strategies for reducing habitual behaviors in mental disorders.”

https://www.ncbi.nlm.nih.gov/pubmed/30589475

https://onlinelibrary.wiley.com/doi/abs/10.1111/ejn.14330

Weight loss and improved mood after aerobic exercise training are linked to lower plasma anandamide in healthy people.

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Physiology & Behavior

“Anandamide, a major endocannabinoid, participates in energy metabolism homeostasis and neurobehavioral processes. In a secondary analyses of an open-label, randomized controlled trial, we investigated the long-term effect of aerobic exercise on resting plasma anandamide, and explored its relationship with changes in body weight, cardiorespiratory fitness, and mood status in healthy, physically inactive individuals.

Thirty-four participants (age = 38 ± 11.5, BMI = 26.6 ± 3.6) were intention to treat-analysed (Exercise: n = 17; Control: n = 17). After intervention, there were significant decreases in plasma anandamide (p < .01), anger, anxiety, and body weight (all p < .05), whereas cardiorespiratory fitness increased (p < .05) in the exercise group. There were no significant changes in any variable for the control group. In the whole cohort, adjusted R2 of multiple linear regressions showed that 12.2% of change body weight was explained by changes in anandamide (β = 0.391, p = .033), while 27% of change in mood disturbance (β = 0.546, p = .003), and 13.1% of change in anger (β = 0.404, p = .03) was explained by changes in anandamide.

Our data suggest that the weight loss and mood improvement through regular moderate exercise may involve changes in anandamide metabolism/signaling.”

https://www.ncbi.nlm.nih.gov/pubmed/30578894

https://www.sciencedirect.com/science/article/abs/pii/S0031938418308254?via%3Dihub