Journal of Neuroscience, Vol 3, 2240-2250, Copyright © 1983 by Society for Neuroscience
Reciprocal changes in the firing rate of neostriatal and dorsal raphe neurons following local infusions or systemic injections of D- amphetamine: evidence for neostriatal heterogeneity
GV Rebec and SD Curtis
A local infusion of d-amphetamine (d-AMPH) into the dorsal raphe nucleus
(DRN) inhibited neuronal activity in this site and produced a mirror-image
excitation in the ventrolateral, but not dorsomedial, neostriatum. This
effect, which was mimicked by 5-methoxy-N,N- dimethyltryptamine, a
serotonin autoreceptor agonist, was not altered by pretreatment with
alpha-methyl-p-tyrosine. Similar regional differences in neostriatal
activity were obtained following an electrolytic lesion of the DRN or an
intraperitoneal injection of d- AMPH. In fact, whereas 1.0 mg/kg of d-AMPH
accelerated ventrolateral activity and inhibited dorsomedial neurons, 7.5
mg/kg produced the opposite effect. At both doses, however, DRN activity
was inversely related to firing rate in the ventrolateral, but not
dorsomedial, neostriatum. These results indicate that only certain regions
of the neostriatum are responsive to changes in DRN activity and that these
regions respond differently to systemic injections of d-AMPH than other
neostriatal sites.