2000, Number 4
Salud Mental 2000; 23 (4)
Neurobiology of addiction: Neuroanatomical, neurochemical, molecular and genetic aspects of morphine and cocaine addiction. Part II
Anton B, Calva JC, Valdez A, Acevedo R, Morales A, Medecigo M, Leff P
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ABSTRACTDrug addiction in humans is a chronically relapsing disorder, that impacts both society and the individual welfare. Both neurochemical and neuropharmacological studies have shown for more than a decade, that most drugs of abuse act through mechanisms that involve the mesocorticolimbic dopamine reinforcement/reward system in the eNS. These drugs, including stimulants such as cocaine and amphetamine; opiates such as morphine and heroin, and legal drugs such as alcohol and nicotine, change the neurochemical function of different neurotransmitter systems in the brain that lead to neuronal responses that converge in the increase activation of ventrotegmental dopamine neurons, and in an elevation of the extracellular dopamine concentration in the nucleus accumbens. Ventrotegmental dopamine neurons send axonal projections to interconnected forebrain structures that mediate many of the reinforcing, behavioral and locomotor effects of most drugs of abuse, such as the prefrontal cortex, striatum and nucle us accumbens. However, other interconnected forebrain structures, such as the amygdala, has been shown to playa crucial role in the brain reward mechanisms and motivational effects produced by these drugs. Thus, most neurochemical changes and neuroadaptations that occur during the development of drug addiction involve cellular and molecular mechanisms that affect both peptidergic and non peptidergic neurotransmission systems that impair the neurochemical function of the mesocorticolimbic neural substrate mediating the acute and chronic reinforcing actions of most drugs of abuse.