Selective D3 Receptor Antagonist SB-277011-A Potentiates the Effect of Cocaine on Extracellular Dopamine in the Nucleus Accumbens: a Dual Core-Shell Voltammetry Study in Anesthetized Rats

Dopamine (DA) D3 receptors have been associated with drug intake and abuse and selectively distribute in the brain circuits responding to drug administration. Here we examined the effects of an acute systemic administration of cocaine (15 mg/kg) alone or preceded by treatment with the selective D3 receptor antagonist SB-277011-A (10 mg/kg) on DA levels concurrently in the rat nucleus accumbens shell and core sub-regions (NAcshell and NAccore, respectively). It is shown that cocaine increases extracellular DA in both compartments and that blocking D3 receptors with SB-277011-A, although the latter is devoid of dopaminergic effects per se, potentiates these effects. No differences in the amplitude of the response were observed between NAcshell and NAccore compartments, though the dopaminergic response in the NAcshell was transient whereas that in the NAccore rose slowly to reach a plateau. These results demonstrate the feasibility to use multiprobe voltammetry to measure discrete monoaminergic responses in discrete areas of the brain and confirm the effect of D3 receptors antagonist at modifying the neurochemical effects of cocaine.