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首页> 外文期刊>American Journal of Physiology >Effect of simulated I(to) on guinea pig and canine ventricular action potential morphology.
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Effect of simulated I(to) on guinea pig and canine ventricular action potential morphology.

机译：模拟I（to）对豚鼠和犬心室动作电位形态的影响。

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摘要

The transient outward current (I(to)) is a major repolarizing current in the heart. Marked reduction of I(to) density occurs in heart failure and is accompanied by significant action potential duration (APD) prolongation. To understand the species-dependent role of I(to) in regulating the ventricular action potential morphology and duration, we introduced simulated I(to) conductance in guinea pig and canine endocardial ventricular myocytes using the dynamic clamp technique and perforated patch-clamp recordings. The effects of simulated I(to) in both types of cells were complex and biphasic, separated by a clear density threshold of approximately 40 pA/pF. Below this threshold, simulated I(to) resulted in a distinct phase 1 notch and had little effect on or moderately prolonged the APD. I(to) above the threshold resulted in all-or-none repolarization and precipitously reduced the APD. Qualitatively, these results agreed with our previous studies in canine ventricular cells using whole cell recordings. We conclude that 1) contrary to previous gene transfer studies involving the Kv4.3 current, the response of guinea pig ventricular myocytes to a fully inactivating I(to) is similar to that of canine ventricular cells and 2) in animals such as dogs that have a broad cardiac action potential, I(to) does not play a major role in setting the APD.
机译：瞬态向外电流（I（to））是心脏中的主要复极化电流。 I（to）密度显着降低发生在心力衰竭中，并伴有明显的动作电位持续时间（APD）延长。为了了解I（to）在调节心室动作电位形态和持续时间方面的物种依赖性作用，我们使用动态钳技术和穿孔膜片钳记录技术在豚鼠和犬心内膜心室肌细胞中引入了模拟I（to）电导。在两种类型的细胞中模拟的I（to）的影响都是复杂的且是两相的，由大约40 pA / pF的透明密度阈值隔开。低于此阈值，模拟的I（to）会导致明显的1期陷波，并且对APD的影响很小或没有适度延长。 I（至）高于阈值导致全极化或全无极化，并急剧降低APD。定性地，这些结果与我们先前使用全细胞记录在犬心室细胞中的研究相吻合。我们得出的结论是：1）与先前涉及Kv4.3电流的基因转移研究相反，豚鼠心室肌​​细胞对完全失活的I（to）的响应类似于犬心室细胞的响应，以及2）在动物（如狗）中具有广泛的心脏动作潜能，I（to）在设定APD方面不发挥主要作用。

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