ATP-dependent K+ and voltage-gated Ca2+ channels in endothelial cells of brain capillaries. Effect of hypoxia.

Abstract

The energy demand of mammalian cells in order to maintain life is closely related to the presence of molecular oxygen. Deficiency in oxygen delivery to tissue therefore activates protective mechanisms to restore the state of high order that characterises life. Endothclial cells, like many other cells of the cardiovascular system, play an important role in this complex machinery that prevent and protect cells of lack in oxygen supply. Capillary endothelial cells per se are able to sense changes in environmental The cellular permeability and ATPase activity of brain capillary endothelial cells is affected when exposed to low or chemically induced hypoxia, respectively (E. Dux et al., 1984; N. Kawai et al., 1996a). Since information is lacking concerning the participation of ion channels and membrane potential in brain capillary endothelial cells during hypoxia, the aim of this study was designed to investigate their ion channel properties and to see whether these channels are involved in the transductory pathway of the protective response to hypoxia, as already known in other cells like type I cells of the carotid body, smooth muscle cells and neuroepithelial cells of the lung (J. Lopez-Barneo, 1996).