토끼 단일 심근세포에서 대사억제시 Inward Rectifier(IK1)의 변화

• 영문명: Effect of Metabolic Inhibition on Inward Rectifier K Current in Single Rabbit Ventricular Myocytes
• 발행기관: 대한생리학회-대한약리학회
• 저자명: 정유정(Yu Jeong Chung) 호원경(Won Kyung Ho) 엄융의(Yung E Earm)
• 간행물 정보: 『The Korean Journal of Physiology & Pharmacology』제1권 제6호, 741~748쪽, 전체 8쪽
• 주제분류: 의약학 > 의학일반
• 파일형태: PDF
• 발행일자: 1997.01.01

영문 초록

In the present study, we have investigated the effect of metabolic inhibition on the inward rectifier K current (I_K1)_. Using whole cell patch clamp technique we applied voltage ramp from ⁢80 mV to ⁣140 mV at a holding potential of ⁣30 mV and recorded the whole cell current in single ventricular myocytes isolated from the rabbit heart. The current-voltage relationship showed N-shape (a large inward current and little outward current with a negative slope) which is a characteristic of I_K1. Application of 0.2 mM dinitrophenol (DNP, an uncoupler of oxidative phosphorylation as a tool for chemical hypoxia) to the bathing solution with the pipette solution containing 5 mM ATP, produced a gradual increase of outward current followed by a gradual decrease of inward current with little change in the reversal potential (⁣80 mV). The increase of outward current was reversed by glibenclamide (10 ㄍM), suggesting that it is caused by the activation of K_ATP. When DNP and glibenclamide were applied at the same time or glibenclamide was pretreated, DNP produced same degree of reduction in the magnitude of the inward current. These results show that metabolic inhibition induces not only the increase of K_ATP channel but also the decrease of I_K1. Perfusing the cell with ATP-free pipette solution induced the changes very similar to those observed using DNP. Long exposure of DNP (30 min) or ATP-free pipette solution produced a marked decrease of both inward and outward current with a significant change in the reversal potential.

Above results suggest that the decrease of I_K1 may contribute to the depolarisation of membrane potential during metabolic inhibition.

키워드

DNP Metabolic inhibition Whole cell patch clamp Inward rectifier K current ATP