Abstract
Repeated cocaine administration results in persistent changes in synaptic function in the mesolimbic dopamine system that are thought to be critical for the transition to addiction. Cytoskeletal rearrangement and actin dynamics are essential for this drug-dependent plasticity. Cocaine administration increases levels of F-actin in the nucleus accumbens and is associated with changes in the phosphorylation state of actin-binding proteins. The adducins constitute a family of proteins that interact with actin and spectrin to maintain cellular architecture. The interaction of adducin with these cytoskeletal proteins is regulated by phosphorylation, and it is therefore expected that phosphorylation of adducin may be involved in morphological changes underlying synaptic responses to drugs of abuse including cocaine. In the current study, we characterized the regulation of adducin phosphorylation in the nucleus accumbens and dorsal striatum in response to various regimen of cocaine. Our results demonstrate that adducin is phosphorylated by protein kinase C in medium spiny neurons that express the dopamine D1 receptor. These data indicate that adducin phosphorylation is a signaling event regulated by cocaine administration and further suggest that adducin may be involved in remodeling of the neuronal cytoskeleton in response to cocaine administration.