Neurobiology of addiction neuroanatomical, neurochemical, molecular and genetic aspects of morphine and cocaine addiction - Part I

Addiction is a serious clinical and social problem that impacts public heal th organizations in many countries. From a medical viewpoint, addiction is a complex neurobiological phenomenon that affects different functional and molecular processes in specific areas of the mammal brain including human. Animal models of addiction have extensively used pharmacological paradigms of drug self administration with the aim of investigating the addictive pro perties of psychotropic substances such as morphine, heroine and cocaine. T hus, studies on these animal models have identified that addictive properti es of these substances depend upon their pharmacological actions for alteri ng the specific neural functions of the mesocorticolimbic dopaminergic circ uitry. Specific electrophysiological, neurochemical and genomic alterations in the mesocorticolimbic dopaminergic pathway have been identified during the development and long-term consolidation of complex behavioral states re lated to drug dependence and reward. This work reviews the current informat ion related to the major electrophysiological and neurochemical alterations that have been observed in the dopaminergic mesocorticolimbic circuitry du ring the addictive processes of morphine, heroin and cocaine.