What is the effect of ghrelin on rat uterine contractility in vitro?

Ghrelin, a recently isolated gastric hormone, is an endogenous ligand for growth hormone secretagogue receptors. There is novel evidence that ghrelin might be expressed in rat ovaries, placental tissues, and the uterus. It has been reported to have modulatory effects on smooth muscle contractility. In this study, we investigated the effects of ghrelin on spontaneous and oxytocin-induced contractions in the rat uterus in vitro and tried to detect its signaling pathway. Myometrium strips were removed from virgin female albino Wister rats and placed in a jacketed tissue bath. After initiation of spontaneous contractions, ghrelin was added to the tissue bath alone or after administration of indomethacin or N -nitro-L-arginine methyl ester (L-NAME) or propranolol HCl. Student’s t-test was used for statistical analysis. Our results revealed an inhibitory effect of ghrelin on both spontaneous and oxytocin-induced myometrial contractions. This effect was not affected by the application of indomethacin or L-NAME but was blocked after propranolol HCl administration. Ghrelin has an inhibitory effect on basal and oxytocin-induced rat myometrial contractions in vitro, and this myometrial response to ghrelin might be mediated by β-receptor signaling pathway.