[Neurobiology of endocannabinoids and central effects of tetrahydrocannabinol contained in indian hemp].

Tetrahydrocannabinol, the main psychotropic component of Cannabis indica, is an addictive drug with multiple effects including both peripheral and central damages. All these effects are due to interference with endocannabinoidergic transmission. This endocannabinoid system subtly regulates many physiologicalfunctions. This regulation involves various ligands derived from arachidonic acid (anandamide, di-arachidonoylglycerol, virodhamin, noladin ether, N arachidonoyl dopamine, etc.) which stimulate two main types of receptor CB1 in the central nervous system and CB2 in the periphery. CB1 receptors are very numerous and ubiquitous in the brain. They influence various important functions (awakening, attention, delirium, hallucinations, memory, cognition, anxiety, humor stability, motor coordination, brain maturation, etc.). Far from mimicking endocannabinoids, THC caricatures their effects. It affects all brain structures, simultaneously, intensely and durably, inducing down-regulation of CB1 receptors and thereby reducing the effects of their physiological ligands. On account of its exceptional lipophilia, THC accumulates for days and even weeks in the brain. It is not a soft drug but rather a slow drug: its abuse induces long-lasting modifications and deterioration of brain function, potentially leading to various mental and psychiatric disorders.