Evidence for Involvement of Both IK _Ca and SK _Ca Channels in Hyperpolarizing Responses of the Rat Middle Cerebral Artery

Abstract

In the absence of NO, IKCa underpins endothelium-dependent hyperpolarization and relaxation in cerebral arteries. However, when NOS is active SKCa contributes to hyperpolarization, whatever the extent of background contraction. These changes may have relevance in vascular disease states where NO release is compromised and when the levels of SKCa expression may be altered.