Endothelial Kir2 channel dysfunction in aged cerebral parenchymal arterioles

Abstract

Advanced age in mice (>2 yr, similar to a 70- to 80-yr-old human) impairs P2Y and Kir2 channel-induced dilation. Reductions in endothelial Kir2 activity were associated with lower vasodilatory response to purinergic receptor activation and increased resting myogenic tone of cerebral arterioles. Paradoxically, vasodilation following Kir2 activation was larger in aged cerebral arterioles, and unaffected by endothelium removal, suggesting a possible compensation by smooth muscle Kir2 channels. However, this compensation was not sufficient to restore purinergic dilation.