Effects of hypoxia on a potassium channel in cat cerebral arterial muscle cells.

We have shown that exposure of isolated cat cerebral arterial muscle cells to hypoxic environments increases K+ channel activity when recorded in the cell-attached mode. Inhibition by glibenclamide of the "hypoxia-induced" increase in K+ channel activity may suggest that increased activity is mediated by an ATP sensitive K+ channel. Thus, the level of O2 may modulate cerebral vascular tone by an action on membrane K+ channels, possibly mediated by the concentration of intracellular ATP.