Cocaine, but not amphetamine, short term treatment elevates the density of rat brain vesicular monoamine transporter 2.

We compared the effect of 5 days D-amphetamine (5 mg/kg/day i.p.) and cocaine (15 mg/kg/day i.p.) administration on the vesicular monoamine transporter 2 (VMAT2) density in rat brain. VMAT2 expression was assessed by [(3)H]dihydrotetrabenazine high affinity binding. Cocaine administration led to significant increases in VMAT2 density in both prefrontal cortex (+40%, p < 0.01) and striatum (+23%, p < 0.05), while amphetamine did not affect VMAT2 expression. The upregulation of VMAT2 may serve as compensatory mechanism aimed to enhance the vesicular monoamine storage capacity.