동방결절에서 Ouabain에 의하여 발생하는 일과성 내향전류(TI)에 관한 연구

• 영문명: A Study on the Ouabain-induced Transient Inward Current(TI) in the Rabbit Sinoatrial Node
• 발행기관: 대한생리학회
• 저자명: 최정연(Choi, Jung-Yun) 홍창의(Hong, Chang-Yee) 엄융의(Earm, Yung-E)
• 간행물 정보: 『대한생리학회지』제19권 제2호, 101~112쪽, 전체 12쪽
• 주제분류: 의약학 > 의학일반
• 파일형태: PDF
• 발행일자: 1985.12.31

영문 초록

Transient inward current (TI) was studied by the two micro-electrode voltage clamp technique in the sinoatrial node of the rabbit. The author confirmed that in 10^-6 M ouabain TI was found in the SA node and investigated the effects of ions, (Na⁺, K⁺, Ca²⁺, β-agonist (isoprenaline), local anesthetics (quinidine, lidocaine) and Ca-blockers (Co²⁺, verapamil, diltiazem) on the TI recorded during depolarizing voltage clamp pulses to -40 and -20 mV. The results obtained were as follows ; 1) 10^-6 M ouabain increased the frequency of sinus action potential and decreased the amplitude, especially overshoot of action potential. TI was induced by the depolarizing voltage clamp Pulses and the magnitude of the slow inward current (isi) decreased and the time course was slowed by the same depolarizing pulses. 2) 30% Na⁺ and 24mM K⁺ decreased by 10^-6 M ouabain and 6 mM Ca²⁺ and 10^-7 M isoprenaline increased TI, i_si and current oscillations. 3) Quinidine 5 X 10^-7M) reduced TI and i_si but lidocaine (10⁶ -10^-5 M) didn t reduced or increase TI. Current oscillations increased and isi decreased by lidocaine. 4) Ca-blockers decreased the amplitude and the frequency of sinus action potential. TI and i_si decreased significantly but were not abolished completely at the concentrations used in this experiment. Verapamil and diltiazem had inhibitory action on TI in 2 X 10^-7M concentration and showed very slow recovery after wasting out with normal Tyrode solution.