Regulation of Human Coronary Vascular Tone: Further Evidence Must Be Sought Before Ruling Out the Direct Role of ATP-Sensitive Potassium Channels in Regulation of Coronary Vasculature

Abstract

To the Editor: The study by Kakkar et al in Circulation Research established that spontaneous coronary vasospasm in ATP-sensitive potassium channels (K+ ATP channels) mutant mice arises from a smooth-muscle extrinsic process.1 We congratulate the investigators for successfully accomplishing such meticulous research. The concluding hypothesis, which points toward a multiorgan involvement or a paracrine cross-talk effect of neuronal or endothelial K+ ATP channels to vascular smooth muscle (VSM) in the event of coronary vasospasm, is very novel and appealing. The elucidated finding, which negates a direct role of VSM K+ ATP channels in tone regulation of coronary vasculature, is very striking as a direct implication of the VSM K+ ATP channels is well established in extracoronary vasculatures.2–4 We recommend a scrupulous exploration into the matter before any direct, or indirect, conclusions can be made. In our study on isolated …