EFFECTS OF CGRP ON ACTIVE-AVOIDANCE BEHAVIOR IN RATS

The effect of calcitonin gene-related peptide (CGRP) on the extinction of active avoidance behaviour was examined in rats. Three doses (250 ng, 500 ng and 1 mu g) of the peptide were administered into the later al brain ventricle (i.c.v.). CGRP delayed the extinction of an active avoidance response in a dose-dependent manner. To reveal any role of t he transmitter systems in the action of exogenously administered CGRP, the animals were pretreated with different receptor blockers. CGRP in duced a delay in the extinction of an active avoidance response, which could be prevented by haloperidol, propranolol, methysergide and nalo xone. Phenoxybenamine, atropine and bicuculline were ineffective. The data suggest that dopaminergic, beta adrenergic, serotonergic and opia te transmission are involved in the CGRP-induced behavioral alteration s.