Cocaine induced dopamine sensitization is absent in mice lacking the preproenkephalin gene?.

MONGI BRAGATO B; GARCÍA KELLER C; ZIMMER A; CANCELA LILIANA

Workshop; II International Workshop Motivated behavior, stress and addiction: from molecules to behavior; 2012

Repeated administration of cocaine induces psychomotor sensitization, characterized by an augmented locomotor response to a subsequent cocaine challenge. Among the enduring neuronal changes responsible for the expression of cocaine sensitization, alterations in glutamate and dopamine signaling, as well as plasticity within the nucleus accumbens and striatum play a critical role. However, it has been described that not only the glutamatergic and dopaminergic system are involved in this phenomenon but also the enkephalinergic and opioid systems. Opioid receptors and endogenous opioid peptides, mainly enkephalin, are largely distributed in the mesolimbic system. However, their contribution to cocaine - induced sensitization on behavioral and neurochemical associated parameters has been poorly studied.