Activity of eledoisin, other polypeptides and ergometrine on the uterus in situ of rabbit and other animal species

Abstract

The oxytocic activity of eledoisin on the uterus in situ of different animal species has been studied and compared with other oxytocic drugs. Eledoisin stimulated the rabbit uterus at doses as low as 0·01-0·1 μg/kg i.v. but had no significant oxytocic action on the uterus of cat, rat, and guinea-pig. It is, however, more active on the vascular than on the non-vascular smooth muscle preparations of the same animal species. The oxytocic activity of oxytocin and ergometrine, on the other hand, has been confirmed on almost all the animal species studied in doses which did not significantly alter the blood pressure (at least in the rabbit). In the rabbit the oxytocic effect of ergometrine but not that of eledoisin and oxytocin was abolished by the adrenolytic drugs dibenzyline, piperoxan and hydergine. Hypertensin also stimulated almost all the uteri tested, whilst bradykinin was not active in the doses used.