d-Amphetamine-induced inhibition of central dopaminergic neurons: mediation by a striato-nigral feedback pathway.

Lesions of the striato-nigral pathways (that is, crus cerebri or vicinity of the tail of the caudate nucleus) markedly attenuate depressant effects of intravenous d-amphetamine on central dopaminergic cell activity. These results, coupled with previous data showing that microiontophoretic application of d-amphetamine directly onto dopaminergic cells does not produce significant slowing, provide direct support for the hypothesis that the depressant effect of d-amphetamine on these cells is mediated through a striato-nigral neuronal feedback loop.