The potential role of cannabinoids in modulating serotonergic signaling by their influence on tryptophan metabolism

Abstract

Phytocannabinoids present in Cannabis plants are well known to exert potent anti-inflammatory and immunomodulatory effects. Previously, we have demonstrated that he psychoactive Δ9-tetrahydrocannabinol (THC) and the non-psychotropic cannabidiol CBD) modulate mitogen-induced Th1-type immune responses in peripheral blood ononuclear cells (PBMC). The suppressive effect of both cannabinoids on mitogeninduced ryptophan degradation mediated by indoleamine-2,3-dioxygenase (IDO), suggests n additional mechanism by which antidepressive effects of cannabinoids might be linked to the serotonergic system. Here, we will review the role of tryptophan metabolism in the course of cell mediated immune responses and the relevance of cannabinoids in erotonergic signaling. We conclude that in particular the non-psychotropic CBD might be useful for the treatment of mood disorders in patients with inflammatory diseases, since this cannabinoid seems to be safe and its effects on activation-induced tryptophan degradation by CBD were more potent as compared to THC. © 2010 by the authors.