A Study On The Effect Of Calcitoningene Related Peptide On Uterinecontractility In Experimental Animals

Calcitonin gene-related peptide ( CGRP) is a potent vasodilator andrelaxes smooth muscles of a variety of tissues , but the effects of CGRP onmyometrial contractions and its mechanism/s of action are not clear. Thepurpose of the study was to investigate (1) Whether uterine relaxationresponses to CGRP are differentially regulated during pregnancy and labor.(2) The involvement of CGRP-receptors, Nitric oxide (NO) , and / or Ca++activated I(’ channels in smooth muscle relaxant action of CGRP in the ratuterus.In order to achieve the aim of this work thirty (30) healthy adultalbino rats, 24 females for the experiments and 6 males for induction ofpregnancy were used. The estrus phase of the estrus cycle was detected bythe presence of increased number of cornified epithelial cells in vaginalsmears. The females proved to be in the estrus phase were paired withmature male rats in separate cages, after that males were isolated. The firstday of gestation was detected by the presence of sperms in the femalevagina.The animals (female rats) were divided into four equal groups: each groupconsisted of 6 female rats (6 animals on day 18`h of gestation, 6 animals onthe day 22th of gestation and 6 animals on day 2 postpartum) to study theeffects of CGRP on the spontaneous contractile activity of isolated myometrial strips and 6 animals on day 18th of gestation to study thepossible mechanism(s) of action of CGRP on the spontaneous contractilityof isolated myometrial strips in presence of CGRP8_37, L-NAME andTetra-ethylammonium chloride