Neurotensin concentrations in rat striatum and nucleus accumbens: Further studies of their regulation.
The possible influence of cholinergic and dopaminergic mechanisms on neurotensin-containing neurones was examined at two different levels; nucleus accumbens and striatum in the rat brain. The acute treatment with the anticholinergic drugs atropine and scopolamine increased neurotensin concentrations in the striatum and, in the former case, also in the nucleus accumbens. Subchronic administration of atropine resulted in tolerance to its neurotensin-elevating action within the accumbens, but not within the striatum. Combined treatment with submaximal doses of haloperidol and atropine resulted in increases in neurotensin content which were greater than those seen with either agent alone. This was true regardless of whether the drugs were administered acutely or subchronically. This observation demonstrated that the tolerance phenomena occurring after subchronic elozapine and fluperlapine were not attributable to their anticholinergic activity. The control of striatal and accumbal neurotensin content by antidopaminergic and anticholinergic drugs seemed to be quite specific: drugs with actions on noradrenergic, serotoninergic, GABA-ergic and opiate systems did not influence the neurotensin content in these two structures. Preliminary studies on the effects of haloperidol on neurotensin release from striatal slices in vitro and that of cycloheximide on haloperidol's effect in vivo, suggest a possible inhibitory action of dopamine receptor blockade on neurotensin release.
Frey
P
P
Sandoz Research Institute Berne Ltd, P.O. Box 2173, 3001 Berne, Switzerland.
Lis
M
M
Coward
D M
DM