Integrin expression is altered after acute and chronic cocaine.

Cocaine addiction is associated with an increase in actin cycling and alterations in dendritic spines in the nucleus accumbens. Both actin polymerization and spine morphology are regulated in part by beta-(beta) integrins. Mice were administered acute or daily injections of cocaine or saline for 7 days. After 3 weeks of withdrawal, the level of beta-integrins in the postsynaptic density enriched subfraction from nucleus accumbens tissue was quantified by immunoblotting at 0, 30 or 120min following an a cocaine challenge injection. After chronic treatment and withdrawal the basal level of beta1-integrin was increased while beta3-integrin was unaltered. However, following a cocaine challenge in chronic cocaine, but not saline-treated animals, beta3-integrin was transiently up-regulated while beta1-integrin was transiently downregulated. These data demonstrate a bidirectional regulation of beta-integrins by chronic cocaine treatment that may contribute to cocaine-induced changes in actin cycling and dendrite morphology.