Jeck C D, Rosen M R
Columbia University College of Physicians and Surgeons, New York, New York.
J Pharmacol Exp Ther. 1990 Nov;255(2):738-43.
Tissues from different areas of the heart and from animals of different ages are not uniform in regard to their action potential characteristics. Thus, they would not be expected to respond homogeneously to pathological processes or cardioactive drugs. Our objectives were to determine the age-related changes in canine epicardial and guinea pig papillary muscle transmembrane potentials and to determine the age-related effects of lidocaine on these tissues. Standard microelectrode techniques were used. We found the neonatal canine epicardial action potential plateau to be more positive and rounded and the action potential duration to be longer than that of the adult epicardium. In contrast, guinea pig papillary muscles did not show any differences in neonatal and adult transmembrane potentials. Significant age-related differences in the use-dependent effects of lidocaine were found in the canine epicardial tissue. The neonatal epicardium reached a steady-state level of block more rapidly and recovered from this block more slowly when compared to the adult epicardium. The guinea pig papillary muscles showed no age-related differences in the kinetics of use-dependent lidocaine block. These data suggest that age-related differences in the voltage-time course of the action potential plateau and repolarization may be largely responsible for the age-related differences seen in lidocaine's effects on canine epicardium.
来自心脏不同区域以及不同年龄动物的组织，其动作电位特征并不一致。因此，预计它们对病理过程或心脏活性药物的反应也不会相同。我们的目标是确定犬心外膜和豚鼠乳头肌跨膜电位随年龄的变化，并确定利多卡因对这些组织的年龄相关影响。采用了标准微电极技术。我们发现新生犬心外膜动作电位平台期更正且更圆，动作电位时程比成年心外膜更长。相比之下，豚鼠乳头肌在新生和成年时的跨膜电位没有差异。在犬心外膜组织中发现了利多卡因使用依赖性效应存在显著的年龄相关差异。与成年心外膜相比，新生心外膜达到稳态阻滞水平更快，从这种阻滞中恢复更慢。豚鼠乳头肌在利多卡因使用依赖性阻滞动力学方面未显示出年龄相关差异。这些数据表明，动作电位平台期和复极化的电压 - 时间过程中与年龄相关的差异，可能在很大程度上导致了利多卡因对犬心外膜作用中所观察到的年龄相关差异。
