細胞外鉀離子濃度對鼠橫膈肌細胞內鈉離子活性之影響

Effect of Extracellular Potassium on Intracellular Sodium Ion Activity in Diaphragmatic Skeletal Muscle of Rat

楊忠謀(Jung-Mou Yang) ； 楊生湳(Shan-Nan Yang) ； 林正一(Cheng-I Lin)

《Journal of Medical Sciences》 10卷1期 (1989/02) Pp. 33-38

摘要

The purpose of this study was to measure intracellular sodium ion activities in skeletal muscle and to explore the relationship between cell membrane potntial and sodium ion activity. A piece of diaphragmatic muscle was fixed on the floor of perftusion chamber and circumfused with Tyrod solution. In six different preparation, the cell membrane potential was -86.2 ± 4.5 mV, cytosolic sodium ion activity was 16.5 ± 1.7 mM in control condition. When the muscle was in condition of low [Na^+]o (20mM), cell membrane potential changed from control -80.4 ± 3.2 mV to -83.4 ± 7.5 mV, cytosolic sodium ion activity decreased from 16.5 ± 2.0 mM to 11.9 ± 3.0 mM (n=3, p ＜ 0.05); when the muscle was in circumfusion of high [k^+]o (62 mM), cell membrane potential depolarized from control -91.9 ± 3.0 mV to -59.0 ± 5.2 mV, cytosolic sodium ion activity decreased from 16.4 ± 1.4 mM to 10.9 ± 0.6 mM (n=3, p ＜ 0.05). These results reveal that intracellular sodium ion activity parallels with decrement of the electrochemical gradient of soddium across the cell membrane.

關鍵字

骨骼肌 ； 細胞膜電位 ； 鈉離子活性濃度

並列摘要

The purpose of this study was to measure intracellular sodium ion activities in skeletal muscle and to explore the relationship between cell membrane potntial and sodium ion activity. A piece of diaphragmatic muscle was fixed on the floor of perftusion chamber and circumfused with Tyrod solution. In six different preparation, the cell membrane potential was -86.2 ± 4.5 mV, cytosolic sodium ion activity was 16.5 ± 1.7 mM in control condition. When the muscle was in condition of low [Na^+]o (20mM), cell membrane potential changed from control -80.4 ± 3.2 mV to -83.4 ± 7.5 mV, cytosolic sodium ion activity decreased from 16.5 ± 2.0 mM to 11.9 ± 3.0 mM (n=3, p ＜ 0.05); when the muscle was in circumfusion of high [k^+]o (62 mM), cell membrane potential depolarized from control -91.9 ± 3.0 mV to -59.0 ± 5.2 mV, cytosolic sodium ion activity decreased from 16.4 ± 1.4 mM to 10.9 ± 0.6 mM (n=3, p ＜ 0.05). These results reveal that intracellular sodium ion activity parallels with decrement of the electrochemical gradient of soddium across the cell membrane.

並列關鍵字

Skeletal muscele ； Cytosolic Na^+ activity