단일심근 세포의 활동전압 및 막전류에 대한 Na-Ca 교환기전의 영향

• 영문명: Effect of Na-Ca Exchange on the Action Potential and the Membrane Current of Rabbit Atrial Cells
• 발행기관: 대한생리학회
• 저자명: 호원경(Ho, Won-Kyung) 서인석(So, In-Suk) 엄융의(Earm, Yung-E)
• 간행물 정보: 『대한생리학회지』제23권 제2호, 313~328쪽, 전체 16쪽
• 주제분류: 의약학 > 의학일반
• 파일형태: PDF
• 발행일자: 1989.12.31

영문 초록

The electrophysiological properties of the inward current contributing to the late plateau phase of the action potential were investigated using the whole cell clamp technique and intracellular dialysis in single atrial cells isolated from the rabbit heart. The inward current was activated by various repolarizing pulses after a brief depolarizing pulse to +40 mV for 2 ms and its time course was similar to that of the late plateau of the action potential. The current was fully activated above the potential of -40 mV and abolished by intracellular EGTA. Ryanodine of 1μM also abolished the late plateau and the inward current. Reduced Na_o to 30% and 20 mM Na₁ diminished the late plateau together with the inward current. Diltiazem blocked the activation of the current and Ni in the concentration of 40 ~ 200 μM decreased the development of the late plateau and the inward current. Fully activated current-voltage relation of the inward current showed exponential voltage dependency which was steeper in more hyperplarizing range. The above findings suggest that the inward current was activated by intracellular calcium and contribute the late plateau phase of the action potential. It could be concluded that the inward current would be the inward component of Na-Ca exchange.

키워드

Atrial cell Late plateau phase Na-Ca exchange Whole cell clamp Inward current