Centrally administered neurotensin: activity in the Julou-Courvoisier muscle relaxation test in mice.

Intracisternal (IC) neurotensin (NT) produces muscle relaxation in the Julou-Courvoisier traction test, a screening procedure utilized for assessing neuroleptic drug activity. A dose-response relationship was not observed. IC administration of thyrotropin-releasing hormone (TRH) totally abolished the effects of NT. Two other peptides, substance P and bradykinin, were inactive in the traction test. These data provide further evidence for CNS effects on NT and indicate that this peptide exerts neuroleptic-like activity in a screening test for antipsychotic agents.