ANALYSIS OF ANATOMICAL SITES AT WHICH GALANIN IMPAIRS DELAYED-NONMATCHING-TO-SAMPLE IN RATS

Galanin, a neuropeptide that coexists with acetylcholine in the septoh ippocampal pathway of the rat, impairs operant delayed nonmatching to sample (DNMTS) when administered intracerebroventricularly. Microinjec tion experiments were conducted to determine the anatomical site or si tes at which galanin acts to disrupt DNMTS. Galanin (0.1, 0.4, or 1.6 nmol) was microinjected into the ventral hippocampus, amygdala, nucleu s basalis magnocellularis, prefrontal cortex, or entorhinal cortex. Ga lanin disrupted DNMTS in a dose-dependent manner when microinjected in to the ventral hippocampus but not at the other sites tested. These fi ndings are consistent with the ability of galanin to inhibit physiolog ical and biochemical actions of acetylcholine in the ventral hippocamp us.