Decreased inward rectifier and voltage-gated K+ currents of the right septal coronary artery smooth muscle cells in pulmonary arterial hypertensive rats

• 발행기관: 대한생리학회-대한약리학회
• 저자명: Sung Eun Kim Ming Zhe Yin Hae Jin Kim Rany Vorn Hae Young Yoo Sung Joon Kim
• 간행물 정보: 『The Korean Journal of Physiology & Pharmacology』제24권 제1호, 111~119쪽, 전체 9쪽
• 주제분류: 의약학 > 의학일반
• 파일형태: PDF
• 발행일자: 2020.01.31

영문 초록

In vascular smooth muscle, K+ channels, such as voltage-gated K+ channels (Kv), inward-rectifier K+ channels (Kir), and big-conductance Ca2+-activated K+ channels (BKCa), establish a hyperpolarized membrane potential and counterbalance the depolarizing vasoactive stimuli. Additionally, Kir mediates endotheliumdependent hyperpolarization and the active hyperemia response in various vessels, including the coronary artery. Pulmonary arterial hypertension (PAH) induces right ventricular hypertrophy (RVH), thereby elevating the risk of ischemia and right heart failure. Here, using the whole-cell patch-clamp technique, we compared Kv and Kir current densities (IKv and IKir) in the left (LCSMCs), right (RCSMCs), and septal branches of coronary smooth muscle cells (SCSMCs) from control and monocrotaline (MCT)- induced PAH rats exhibiting RVH. In control rats, (1) IKv was larger in RCSMCs than that in SCSMCs and LCSMCs, (2) IKv inactivation occurred at more negative voltages in SCSMCs than those in RCSMCs and LCSMCs, (3) IKir was smaller in SCSMCs than that in RCSMCs and LCSMCs, and (4) IBKCa did not differ between branches. Moreover, in PAH rats, IKir and IKv decreased in SCSMCs, but not in RCSMCs or LCSMCs, and IBKCa did not change in any of the branches. These results demonstrated that SCSMC-specific decreases in IKv and IKir occur in an MCT-induced PAH model, thereby offering insights into the potential pathophysiological implications of coronary blood flow regulation in right heart disease. Furthermore, the relatively smaller IKir in SCSMCs suggested a less effective vasodilatory response in the septal region to the moderate increase in extracellular K+ concentration under increased activity of the myocardium.

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INTRODUCTION

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DISCUSSION

키워드

Coronary artery Inward rectifier K+ channel Pulmonary arterial hypertension Potassium channel Smooth muscle