The vasorelaxant effect of viscum album leaf extract is nediated by calcium-dependent mechanisms

Viscum album leaf extract has a folk reputation as an antihypertensive agent in Nigeria. Evidence suggests that it has a relaxant effect on smooth muscle. The present study was designed to investigate the role of calcium in the vasorelaxant effect of this extract. Concentration response studies to noradrenaline, KCl and CaCl2 were carried out in rat aortic rings with and without the extract in physiological salt solution (n=6 each). Also the role of intracellular calcium mobilisation was studied by measuring the phasic response to noradrenaline in Ca2+-free EGTA physiological salt solution (n=6). The contractile responses to noradrenaline or KCl were attenuated (