IN-VIVO CENTRAL ACTIONS OF RAT AMYLIN

The purpose of the present study was to examine and compare the profil e of neurobehavioral effects of rat amylin (r-amylin) and rat calciton in gene-related peptide (rCGRP), two peptides having a 50% structural homology. The effects of synthetic r-amylin and rCGRP administered in several doses (0.312-80.0 mu g) into the lateral cerebro-ventricle of rats on spontaneous activity, muscular tone, body temperature, nocicep tion, food intake as well as their potential for inducing catalepsy, w ere investigated, Intraventricular administration of r-amylin or rCGRP significantly reduced spontaneous motor activity and markedly increas ed body temperature of animals in a dose-dependent related fashion, rC GRP produced a significant increase in muscular tone and induced catal eptic effect in animals, but r-amylin had no effect on these variables . Furthermore, neither r-amylin nor rCGRP were able to induce any sign ificant effect on nociceptive response time of animals in the tail imm ersion test even with doses as large as 80.0 mu g. Finally, the two pe ptides did not affect ad libitum food intake, but significantly reduce d food consumption in 22 h food-deprived animals. Together, the result s of the present study suggest that amylin may be involved in a divers ity of neurophysiological processes but displays a different profile o f neurobehavioral effects to that of CGRP which may involve different receptors.