Stimulation of locomotor activity by intra-accumbens AMPA is not inhibited by neonatal 6-hydroxydopamine-induced lesions.

The involvement of dopamine in the hypermotility responses to amphetamine s.c. or AMPA injected into the nucleus accumbens was evaluated in adult rats depleted of dopamine as neonates with 6-hydroxydopamine. The hypermotility response to amphetamine was markedly inhibited in the lesioned animals, while that to AMPA was enhanced. In addition, the hypermotility produced by AMPA in these rats was not inhibited by sulpiride+SCH-23390; however, it was inhibited completely by alpha-methyl-p-tyrosine. These results suggest that the hypermotility produced by AMPA requires endogenous dopamine, but is mediated by a different mechanism than that produced by amphetamine.