• 作者： 蘇銘嘉; 馬丁摩瑞
• 作者服務機構： 臺大醫學院藥理研究所; 賓州大學生理學系
• 中文摘要： 本實驗利用膜電位鉗定方法來探討 Quinidine 與 Lidocaine之在青蛙心肌之作用。在含鈣溶液中，Quinidine 使動作電位週期略微延長但收縮力明顯減弱。但 Lidocaine 使動作電位週期縮短而收縮力不太改變。在河豚毒素存在下，Quinidine 使動作電位週期明顯延長，收縮力明顯減少，但 Lidocaine 作用不明顯。在膜電位鉗定實驗發現 Quinidine在河豚毒素不存在時，會使鈉離子最大流入量減少，而在河豚毒素存在時則最大電流流入量反而增加。Lidocaine 對電流最大流入量不影響。Quinidine 增加電流流入量之作用在心肌浸於鍶溶液時不復存在，相反的，電流最大流入量反而被 Quinidine 減少。Lidocaine 僅使-channel 之鉀離子流量略為增加，但 Quinidine 使鉀離子流量明顯減少。在鎳離子加入浸浴於鈣溶液標本時，動作電位 plateau 減低且鈣離子流入量減少，但動作電位高度則不受鎳影響。在此標本，Lidocaine 使動作電位週期縮短，穩定狀態時電流流出量增加，但動作電位高度不變。在河豚毒素處理時，Lidocaine不再使穩定狀態電流流出量增加。在鎳離子處理之心肌，Quinidine 不但使動作電位週期縮短亦使動作電位高度減少。以上這些結果可解釋 Quinidine 與 Lidocaine 在心肌藥理作用之差異。
• 英文摘要： The effects of quinidine and lidocaine on frog ventricle were studied by using a single sucrose gapvoltage clamp technique. In -Ringer, quinidine (80 μM) caused slight prolongation of action potentialduration and significant inhibition of twitch tension. Lidocaine (40 μM) shortened without significant effect on twitch tension. In tetrodotoxin (TTX)-treated preparations, quinidine causedsignificant prolongation of from 529±19 msec to 597±11 msec, (n=9) and inhibition of twitchtension, but lidocaine did not affect and twitch tension. Under voltage clamp condition, quinidinereduced peak inward current in the absence of TTX, but enhanced peak inward current in the presence ofTTX. The steady state outward current was increased by quinidine. Lidocaine didn't affect peak inwardcurrent in the absence or in the presence of TTX. Membrane current through the inward rectifierwas slightly increased by lidocaine, but significantly inhibited by quinidine. The ehnancement of peak inward current by quinidine was retarded or reversed in preparationbathed with -Ringer. When was added to a preparation bathed in -Ringer, an inhibition ofcalcium inward current and action potential plateau was observed. The spike amplitude of the actionpotential was, however, unaffected by . In this -treated preparation, lidocaine (20 μM) causedsignificant shortening of without significant effect on action potential amplitude. The shorteningof was associated with a slight increase of steady state outward current. The increase of steadystate outward current by lidocaine was absent in the TTX-treated preparation. Quinidine (20 μM)shortened with significant inhibition of the action potential amplitude. These results can explainthe pharmacological differences between quinidine and lidocaine on cardiac muscle.
• 中文關鍵字： Lidocaine-Quinidine-Na channel-Ca channel-K Channel
• 英文關鍵字： --