Furukawa Y, Saegusa K, Chiba S
Jpn Heart J. 1986 Mar;27(2):223-32. doi: 10.1536/ihj.27.223.
Effects of ouabain, CaCl2 and verapamil on the frequency-force relationship (FFR) were investigated in the isolated, blood-perfused dog atrial muscle preparation. When ouabain (3 and 10 micrograms) or CaCl2 (0.5, 1 and 2 mg/min) was given into the sinus node artery, the contractile force of the atrial muscle, driven at a constant pacing rate of 2 Hz, increased dose-dependently. Verapamil (1 and 3 micrograms) decreased the atrial contractile force dose-dependently. When the pacing rate was changed from 2 to 3.5 Hz, the atrial contractile force increased in parallel with the pacing rate (positive FFR). After treatment with ouabain and verapamil, the contractile force declined at higher frequencies (negative FFR). The verapamil-induced negative FFR was much steeper than the ouabain-induced relationship. An infusion of CaCl2 modified the FFR such that higher doses of CaCl2 elicited a negative FFR only at higher pacing rates. However, the CaCl2-induced FFR did not differ from the negative FFR induced by verapamil or ouabain. It was demonstrated that the cardiotonic agents ouabain and CaCl2, as well as verapamil induced negative FFR in the isolated dog heart.
在离体、血液灌注的犬心房肌标本中研究了哇巴因、氯化钙和维拉帕米对频率-力关系（FFR）的影响。当将哇巴因（3和10微克）或氯化钙（0.5、1和2毫克/分钟）注入窦房结动脉时，以2赫兹的恒定起搏频率驱动的心房肌收缩力呈剂量依赖性增加。维拉帕米（1和3微克）使心房收缩力呈剂量依赖性降低。当起搏频率从2赫兹变为3.5赫兹时，心房收缩力与起搏频率平行增加（正性FFR）。用哇巴因和维拉帕米处理后，收缩力在较高频率时下降（负性FFR）。维拉帕米诱导的负性FFR比哇巴因诱导的关系陡峭得多。氯化钙输注改变了FFR，使得仅在较高起搏频率下更高剂量的氯化钙才引发负性FFR。然而，氯化钙诱导的FFR与维拉帕米或哇巴因诱导的负性FFR没有差异。结果表明，强心剂哇巴因和氯化钙以及维拉帕米在离体犬心脏中诱导负性FFR。
