時間非依存性電流の洞結節ペースメーカ電位における役割のコンピュータ・シミュレーションによる検討

概要

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The pacemaker potential of the mammalian sinoatrial node cells consist of various timedependent ionic currents, such as the calcium current, the delayed outward potassium current and the hyperpolarization-activated current. Recently, the presence of the time-independent background current sensitive to external Na (Ib), the Na-K pump current (Ip) have been found in rabbit sinoatrial node cells. We investigated the roles of the time-independent currents in sinoatrial node cells revealed by mathematical models. Ib was expressed by Goldman-Hodgkin-Katz equations, and Ip was expressed using an original model based on the Chapman-Johnson-Kootsey chemical model. According to these models, it was found that Ip of around 9pA contributed to the pacemaker potential. Ib contributed as inward current during pacemaker potential, and its amplitude was around 12 pA, respectively. These results suggest that relatively large time-independent currents contribute to the pacemaker potential of mammalian sinoatrial node cells. It was suggested that other than time-dependent currents, time-independent currents play an important role in the formation of the pacemaker potential in sinoatrial node cells.
東京女子医科大学の論文
2001-12-25