2013 – SUMMARY. In the last years, numerous researches led to identify endocannabinoid system, a sophisticated short-range signaling system which is located both in Central Nervous System (CNS) and in whole organism. Because of its flexibility of expression, it plays a modulatory role in controlling the answers to stimuli which disturb homeostasis. On one hand it lets them occur whilst on the other it limits them in order to protect organism from consequences due to excessive reaction. In the CNS, endocannabinoid system is able to control the release of several neurotransmitters thanks to its retrograde signaling, modulating synaptic activity. Analysing this property during preclinical studies, it came out that the endocannabinoid system is involved in numerous physiologic processes, such as neuroendocrine axes, food consumption, brain reward and satisfaction mechanisms, memories storing and extinction, emotions and neurodevelopment regulation. Such discoveries have led researchers to suppose and investigate an alteration of this system in the physiopathology of some psychiatric disorders such as anxiety disorder, depression, eating disorders, addiction and schizophrenia. Results of such studies on animal models show a possible involvement of this system and were quickly followed by clinical studies which seem to confirm it. These findings might open new scenarios for understanding the pathogenesis of several psychiatric disorders and, at same time, they show new prospects for their treatment.

KEY WORDS: endocannabinoid, retrograde signaling, 2-AG, AEA, CB receptors, synaptic plasticity.