Diez J, Delgado C, Tamargo J
Arch Int Pharmacodyn Ther. 1984 May;269(1):70-82.
The effect of AR-L 115 BS on mechanical and electrical properties of isolated rat atria was investigated. AR-L 115 BS (10(-7) M -5 X 10(-4) M) produced a dose-dependent increase in rate, contractile force and df/dtmax and shortened the sinus node recovery time and the effective refractory period. The increase in contractile force occurred concomitantly with an increase in the height of the plateau of the atrial action potential. The positive inotropic effect produced by AR-L 115 BS depended on the external Ca concentration and was diminished in low Na solution. The drug also decreased the amplitude-interval relationship and post-extrasystolic potentiation. The positive inotropic effect of AR-L 115 BS was inhibited by verapamil and caffeine. These results suggest that in isolated rat atria the positive inotropic effect of AR-L 115 BS might be due to an increase in transmembrane Ca influx into atrial fibres as well as to an effect probably related to the inhibition of Ca sequestration by the sarcoplasmic reticulum.
研究了AR-L 115 BS对离体大鼠心房机电特性的影响。AR-L 115 BS（10⁻⁷M - 5×10⁻⁴M）使心率、收缩力和df/dtmax呈剂量依赖性增加，并缩短了窦房结恢复时间和有效不应期。收缩力的增加与心房动作电位平台期高度的增加同时出现。AR-L 115 BS产生的正性肌力作用依赖于细胞外钙浓度，在低钠溶液中减弱。该药物还降低了波幅-间期关系和期外收缩后增强。AR-L 115 BS的正性肌力作用被维拉帕米和咖啡因抑制。这些结果表明，在离体大鼠心房中，AR-L 115 BS的正性肌力作用可能是由于跨膜钙内流增加进入心房纤维，以及可能与抑制肌浆网钙螯合有关的作用。
