Neuroscience of Drug Addition: Focus on Neural Plasticity (La neuroscienza della tossicodipendenza: la plasticita neuronale)

摘要

Drug addiction is a chronic relapsing disorder characterized by loss of control over drug intake. The latest developments of preclinical and clinical neuroscience of addiction paving the way for new evidence-based therapeutic approaches were presented by a panel of recognized investigators in a Conference held in Rome in September 2002. The major issues discussed were neural plasticity of the addictive cycle, new views on animal models of dependence and possible genetic substrate of individual vulnerability. Glutamate, an excitatory neurotransmitter involved in the neural plasticity, plays a critical role in several aspects of drug addiction including extinction, relapse and cue-controlled craving. Glutamate pathway from the hippocampal formation, the prefrontal cortex and the amygdaloid complex onto the ventral striatum appears critically involved in this respect. Animal models of escalated intake emerge as particularly suitable tools for the investigation of the addictive state. In these models, rodents show different response to drug treatment, stress challenge and fail to maintain homeostatic regulation of reward function. Finally, clinical investigation using genome scan is beginning to reveal candidate genes that might contribute to addiction risk for alcohol and opiate dependence and may be responsible for the perpetuation of the addictive cycle in humans. This, combined with environmental factors, might contribute to specific atypical stress responsivity observed, which might perhaps favor the persistence of addiction.