Does melatonin affect calcium influx in human aortic smooth muscle cells and estradiol-mediated calcium antagonism?

The pineal hormone melatonin showed no effect on voltage-gated calcium channels in cultured human aortic smooth muscle cells. In combination with estradiol, which blocked calcium channels, melatonin did not antagonize the effect of estradiol. It is concluded that melatonin seems to have different effects on voltage-gated calcium channels of divergent cell types since the positive action of melatonin previously observed on rat cardiac membranes by other authors could not be seen in the present investigations with human vascular smooth muscle cells.