Physiological control system, endocannabinoids

Marijuana remains one of the most widely used and abused drugs in the world. Over the past decade there have been major advanees in understanding the mechanisms whereby marijuana interacts with the brain, producing psychoactive and potentially therapeutic effects. Recent findings indicate the existence of an endocannabinoid physiological control system (EPCS) whose role is just beginning to become understood. 

Similar to opioids, the cannabinoid system appears to be intricately involved in normal physiology, specifically in the control of movement, formation of memories, and appetite control. Basic research has discovered that members of this family of compounds have the capacity to protect threatened neurons, thereby slowing neurodegenerative processes that ultimately lead to physical disability. As the function of the physiological role of endocannabinoids becomes clearer, it appears the system may be involved in the pathology of several neurological diseases, specifically multiple sclerosis, spasticity, and pain. In 1999 the German journal, Forschende Komplementar-medizin und Klassische Naturheilkunde (Research in Complementary and Classical Natural Medicine) commented ... 

The endocannabinoid system is implicated in the physiological control of food intake and energy balance, not only after food deprivation but also in animal models of genetic obesity in which it appears to become overactive at the level of both the hypothalamus and adipocytes (Di Marzo et al. 2001c Bensaid et al. 2003). This possibly explains why, following treatment of mice and rats with rimonabant, a transient inhibition of food intake and a more persistent reduction of fat mass are observed (Ravinet-Trillou et al. 2003), and why CBi knockout mice show a reduced susceptibility to obesity in response to a fat diet (Ravinet-Trillou et al. 2004). 

Abstract The endocannabinoid system has been involved in the control of several neurophysiological and behavioural responses. To date, three lines of CBi knockout mice have been established independently in different laboratories. This chapter reviews the main results obtained with these lines of CBi knockout mice in several physiological responses that have been previously related to the activity of the endocannabinoid system. Studies using CBi knockout mice have demonstrated that this receptor participates in the control of several behavioural responses including locomotion, anxiety- and depressive-like states, cognitive functions such as memory and learning processes, cardiovascular responses and feeding. Furthermore,... 

Giuffrida, A., Komelli, D. (2000) The endocannabinoid system a physiological perspective on its role in psychomotor control. Chem. Phys. Lipids 108, 151-158. 

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