[Endocannabinoid system: from metabolic to neuroendocrine effects]

The endocannabinoid system associates the cannabinoid receptors (CB1 and CB2), largely expressed in the central nervous system as well as in the peripheric one, the endocannabinoids (the two main ones being anandamine and the 2 arachidonoyl glycerol), the endocannabinoid-degrading enzymes, and the synthetic antagonists of the CB1 receptor, such as SR141716 (rimonabant). Mechoulam and his team have evidenced the neuroprotector role of endocannabinoids in case of cranial traumatism. As regards the hypothalamo-pituitary-gonadal axis, the administration of endocannabinoids in women would induce a lowering of the LH levels correlating with a loss of its pulsativity. The endocannabinoid system might also play a part in fecondation. In men, endocannabinoids have also been reported as inducing a lowering of LH and as impairing both the motility of the spermatozoa and the acrosomal reaction--a disorder which would be relieved by the administration of the SR141716 antagonist. The endocannabinoid system seems to modulate negatively the activation of the hypothalamo-pituitary-adrenal system. Therefore its stimulation by pharmacological means may suggest new therapies for states of anxiety. Likewise, stimulation of the CB1 receptors might play a role in the activation of the ACTH-secreting cells by CRH. On the peripheric level it is not to be questioned that endocannabinoids play a part in the energetic homeostasis.