Cocaine self-administration for 10 days followed by withdrawal for 1, 30, or 90 days does not alter Cdk5 levels in the rat NAc, but withdrawal for 1 day does increase Cdk5 protein in the rat VTA.117 Cdk5 does not increase in the VTA of sucrose-withdrawn rats. The effect of withdrawal from other drugs on Cdk5 levels and the effect, if any, of increased Cdk5 in the VTA on behavioral signs of cocaine withdrawal are not known.
