Piper H M, Koch R, Spieckermann P G
Basic Res Cardiol. 1985;80 Suppl 1:123-7. doi: 10.1007/978-3-662-11041-6_24.
Ca2+-tolerant ventricular myocytes from adult rats were electrically stimulated. The maximal contraction frequency (fm) was determined at different temperatures. In drug-free Tyrode solution, fm follows the Arrhenius equation from 7 to 39.5 degrees C. However, verapamil introduces a discontinuity around 27 degrees C into the Arrhenius plot of fm. Above this transition temperature the calcium antagonist lowers fm more pronouncedly than below. Below, a tenfold higher concentration is needed for the same relative effect as at 37 degrees C. It is argued that this finding might be important in cardiac surgery when calcium antagonists are used for cardioplegia at deep hypothermia.
对成年大鼠的钙耐受型心室肌细胞进行电刺激。在不同温度下测定最大收缩频率（fm）。在无药物的泰罗德溶液中，从7摄氏度到39.5摄氏度，fm遵循阿伦尼乌斯方程。然而，维拉帕米在约27摄氏度时使fm的阿伦尼乌斯图出现不连续。高于这个转变温度时，钙拮抗剂对fm的降低作用比低于该温度时更明显。在低于该温度时，要产生与37摄氏度时相同的相对效应，所需浓度要高十倍。有人认为，当在深度低温下心内直视手术中使用钙拮抗剂进行心脏停搏时，这一发现可能具有重要意义。
