“Sarcopenic obesity, the combination of skeletal muscle mass and function loss with an increase in body fat, is associated with physical limitations, cardiovascular diseases, metabolic stress, and increased risk of mortality. Cannabinoid receptor type 1 (CB1R) plays a critical role in the regulation of whole-body energy metabolism because of its involvement in controlling appetite, fuel distribution, and utilization. Inhibition of CB1R improves insulin secretion and insulin sensitivity in pancreatic β-cells and hepatocytes. We have now developed a skeletal muscle-specific CB1R-knockout (Skm-CB1R-/-) mouse to study the specific role of CB1R in muscle. Muscle-CB1R ablation prevented diet-induced and age-induced insulin resistance by increasing IR signaling. Moreover, muscle-CB1R ablation enhanced AKT signaling, reducing myostatin expression and increasing IL-6 secretion. Subsequently, muscle-CB1R ablation increased myogenesis through its action on MAPK-mediated myogenic gene expression. Consequently, Skm-CB1R-/- mice had increased muscle mass and whole-body lean/fat ratio in obesity and aging. Muscle-CB1R ablation improved mitochondrial performance, leading to increased whole-body muscle energy expenditure and improved physical endurance, with no change in body weight. These results collectively show that CB1R in muscle is sufficient to regulate whole-body metabolism and physical performance and is a novel target for the treatment of sarcopenic obesity.”
“Evidence suggests that cannabinoid-1 receptor (CB1R) activation is associated with increased food intake and body weight gain. Human epidemiological studies, however, show decreased prevalence of obesity in cannabis users.
Given the overlapping and complementary functions of the cannabinoid receptors (CB1R and CB2R), mice lacking CB2R and mice lacking both CB1R and CB2R were studied.
These results indicate that lacking both CB1R and CB2R protected mice from diet-induced obesity, possibly through the prominent role of CB1R in obesity or through an interactive effect of both receptors.”
“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.”
“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.”
“Endocannabinoids promote energy conservation in obesity, whereas cannabinoid-1 receptor (CB1 R) blockade reverses body weight gain and insulin resistance and increases energy expenditure.
Here we investigated the molecular mechanisms of the catabolic effects of CB1 R blockade in the liver.
CONCLUSION: peripheral CB1 R blockade in obese mice improves glycemic control via the hepatic Sirt1/mTORC2/Akt pathway, whereas it increases fatty acid oxidation via LKB1/AMPK signaling.”
“Cannabinoid receptor type-1 partially mediates metabolic endotoxemia-induced inflammation and insulin resistance. Despite no significant differences in body weight among groups, chronic exposure to low-level LPS altered hepatic endocannabinoid signaling, increased inflammation, and impaired insulin sensitivity and insulin clearance. CB1 inhibition significantly attenuated LPS signaling, which attenuated LPS-induced metabolic alterations. Therefore, we concluded that CB1 contributes to LPS-mediated inflammation and insulin resistance, suggesting that blocking CB1 signaling may have therapeutic benefits in reducing inflammation-induced metabolic abnormalities.”