The role of the endogenous cannabinoid system in peripheral analgesia.

The therapeutic potential of cannabinoids has been studied and investigated through centuries, although many interesting discoveries have emerged from this field in the past decades. Indeed, peripheral analgesic effects of cannabinoids are a new avenue of treatment since they are avoiding the deleterious central side effects of systemic administration. Recently, it has been demonstrated that cannabinoid receptors (more specifically CB(1) and CB(2) receptors) and their endogenous ligands are present at the peripheral level, especially in different layers of skin, and mostly, in the epidermis and dermis. Those findings are reinforcing and confirming the efficacy of peripheral administration of cannabinoids used to alleviate pain in many different animal models. However, many studies have shown that the endocannabinoid system interacts with other receptors and pathways to modulate pain at the peripheral level. Thereof, the main goal of this review is to explain, in a better way, the different interactions regarding the cannabinoid system with other cellular components of its environment, its involvement in the modulation of pain at the peripheral level and, more precisely, in different layers of the skin.