Effects of pallidal neurotensin on haloperidol-induced parkinsonian catalepsy: behavioral and electrophysiological studies.

Abstract

OBJECTIVE: The globus pallidus plays a critical role in movement regulation. Previous studies have indicated that the globus pallidus receives neurotensinergic innervation from the striatum, and systemic administration of a neurotensin analog could produce antiparkinsonian effects. The present study aimed to investigate the effects of pallidal neurotensin on haloperidol-induced parkinsonian symptoms. METHODS: Behavioral experiments and electrophysiological recordings were performed in the present study. RESULTS: Bilateral infusions of neurotensin into the globus pallidus reversed haloperidol-induced parkinsonian catalepsy in rats. Electrophysiological recordings showed that microinjection of neurotensin induced excitation of pallidal neurons in the presence of systemic haloperidol administration. The neurotensin type-1 receptor antagonist SR48692 blocked both the behavioral and the electrophysiological effects induced by neurotensin. CONCLUSION: Activation of pallidal neurotensin receptors may be involved in neurotensin-induced antiparkinsonian effects.