Episodic coronary artery vasospasm and hypertension develop in the absence of Sur2 K(ATP) channels.

K(ATP) channels couple the intracellular energy state to membrane excitability and regulate a wide array of biologic activities. K(ATP) channels contain a pore-forming inwardly rectifying potassium channel and a sulfonylurea receptor regulatory subunit (SUR1 or SUR2). To clarify the role of K(ATP) channels in vascular smooth muscle, we studied Sur2 gene-targeted mice (Sur2(-/-)) and found significantly elevated resting blood pressures and sudden death. Using in vivo monitoring, we detected transient, repeated episodes of coronary artery vasospasm in Sur2(-/-) mice. Focal narrowings in the coronary arteries were present in Sur2(-/-) mice consistent with vascular spasm. We treated Sur2(-/-) mice with a calcium channel antagonist and successfully reduced vasospastic episodes. The intermittent coronary artery vasospasm seen in Sur2(-/-) mice provides a model for the human disorder Prinzmetal variant angina and demonstrates that the SUR2 K(ATP) channel is a critical regulator of episodic vasomotor activity.