萘甲异喹对大鼠心肌细胞Ca~(2+)内流的影响

目的研究萘甲异喹（NI）对大鼠心肌细胞外Ca(2+)内流的影响。方法：应用钙离子荧光指示剂Fura－2检测。结果：NI（3，10μmol·L(-1)）和维拉帕米（0．3μmol·L(－1)）对静息状态下心肌细胞内Ca(2+)浓度无影响，但可浓度依赖地抑制高钾（60mmol·L(-1)）和异丙肾上腺素（lμmol·L(－1)）引起的心肌细胞内Ca(2+)浓度的升高，抑制率分别为29％±6％、49％±9％和26％±6％、40％±8％；NI对两种激动剂作用的抑制百分率无明显差异，而维拉帕米对高钾作用的抑制大于对异丙肾上腺素作用的抑制。结论：NI对心肌细胞电压依赖性钙通道以及和β受体有关的钙通道有阻断作用，NI可能是非选择性钙通道阻滞剂。

The effect of naphthylmethyl isoquinoling on Ca~(2 ) entry at rat myocardial cells

To investigate the effect ofnaphthylmethyl isoquinoline (NI ) on Ca2+ entry.METHODS: Fura-2/AM at freshly isolated ratventricular myocytes. REsULTS: NI had no effect on resting myocardial cells ICa2+ j.; NI (3,10 Hmol. L-1 ) could depress the increase ofventricular myocytes Ca+]. induced by KCl andisoprenaling in concentration dependent manners;the rates of inhibition to KCI and isoprenalineaction were 29%± 6%, 49%± 9% and 26%±6%, 40%± 8% respectively; there was no difference for NI in depressing the increase ofCa'2], induced by two agonists, but the effectof verapamil (0. 3 umol. L -1 ) on KCI was potenter than that on isoprenaline. CONCLUSIONS: NI has the inhibitory effect on Ca2-- entry induced by high K+ and activation ofadrenoceptors, and that NI may be a nonselectivecalcium channel blocker.