Cocaine abuse and its impact on the thymus and spleen

Cocaine is a psychostimulant abused worldwide. Its pharmacotoxicological properties are derived mainly from its impact on the neurotransmission of sympathomimetic nerves. Cocaine enhances and prolongs the neurotransmission of monoamines, such as dopamine, serotonin, and adrenaline, which are responsible not only for cocaine's euphoric effects, but also its cardiovascular toxicity. In addition to these effects on central as well as peripheral nerves, immunosuppression is also implicated in cocaine toxicity. The thymus and spleen are lymphoid organs that are essential in lymphocyte maturation and erythrocyte homeostasis. Reductions in thymus and spleen size, which are observed under both physiological and pathological conditions, are known as thymic involution and splenic contraction, respectively. These phenomena are also observed in experimental animal models of binge cocaine abuse. In this brief review, we describe the mechanisms of cocaine toxicity, thymic involution, and splenic contraction, followed by discussions about the possible role of the latter two phenomena in cocaine intoxication.