Abstract
BackgroundCannabis sativa (also known as marijuana) has been cultivated by man for more than 5,000 years. However, there was a rise in its use in the 20th century for recreational, religious or spiritual, and medicinal purposes. The main psychoactive constituent of cannabis, whose structure was identified in the 1960's, is Δ9-tetrahydrocannabinol. On the other hand, the discovery of cannabinoid receptors and their endogenous agonists took place only very recently. In fact, the first cannabinoid receptor (CB1) was cloned in 1990, followed 3 years later by the characterization of a second cannabinoid receptor (CB2). Since the 19th century, the use of cannabis has been reported to stimulate appetite and increase the consumption of sweet and tasty food, sometimes resulting in significant weight gain. The recent description of the endocannabinoid system, not only in the central nervous system but also in peripheral tissues, points to its involvement in the regulation of appetite, food intake and energy metabolism. Consequently, the pharmacological modulation of the over-activity of this system could be useful in the treatment of the metabolic syndrome.ConclusionsThe endocannabinoid system has important physiological functions not only in the central nervous system but also in peripheral tissues. The activation of central CB1 receptors, particularly in hypothalamic nuclei and in the limbic system, is involved in the regulation of feeding behavior, and especially in the control of the intake of palatable food. In the periphery, cannabinoid receptors are present in adipocytes, skeletal muscle, gastrointestinal tract and liver, modulating energy metabolism.
Highlights
Historical aspects Cannabis sativa has been cultivated by man since approximately 4,000 B.C [1,2]
The insulin resistance that occurs in high-fat diet (HFD)-fed mice is not present in type 1 cannabinoid receptor (CB1)-/- mice. These results led to the conclusion that CB1 receptors are involved in the development of dietinduced obesity and in peripheral metabolic regulations [24]. These results were confirmed by Cota et al [25], who showed that CB1-/- mice exhibit reduced spontaneous caloric intake and total fat mass, decreased body weight, and hypophagia, when compared with CB1 +/+ littermates
It is important to mention that the activation of the endocannabinoid system, in addition to increasing appetite, influences the palatability and the preferential choice of tasty and sweet foods [5] (Figure 2)
Summary
The endocannabinoid system is present and has important physiological functions in the central nervous system and in peripheral tissues. The activation of central CB1 receptors, in hypothalamic nuclei and in the limbic system, is involved in the regulation of feeding behavior, and especially in the control of the intake of palatable food. It is important to mention that the activation of the endocannabinoid system, in addition to increasing appetite (total food intake), influences the palatability and the preferential choice of tasty and sweet foods [5] (Figure 2). Excessive food intake, especially of sweet and palatable food, could lead to the hyperactivity of the endocannabinoid system, resulting in several metabolic alterations typical of the metabolic syndrome (Figure 1). The pharmacological modulation of the endocannabinoid system turns out to be a unique target in the treatment of those that are overweight or obese [41]. All authors read and approved the final manuscript. Competing interests The author declares that they have no competing interests
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
