Walsh K B, Begenisich T B, Kass R S
University of Rochester, School of Medicine and Dentistry, Department of Physiology, NY 14642.
Pflugers Arch. 1988 Feb;411(2):232-4. doi: 10.1007/BF00582323.
The temperature-dependence of the actions of beta-receptor agonists and adenylate cyclase stimulation on both calcium and delayed rectifier potassium channel ionic currents were examined in patch-clamped guinea pig ventricular myocytes. We report that temperature can separate the beta-receptor mediated modulation of potassium and calcium channels. Receptor-mediated increases in the delayed rectifier potassium current, but not the calcium current were very temperature-dependent over the range of 19 to 32 degrees C. At room temperature (19-22 degrees C) the beta-agonist isoproterenol produced a large enhancement of the calcium current but had no effect on the delayed rectifier current. In contrast, at warmer temperatures (28-32 degrees C) both currents increased in the presence of the agonist. This temperature-sensitivity also existed for direct stimulation of adenylate cyclase by forskolin. Thus, cardiac calcium and potassium channels appear to be independently regulated during adrenergic stimulation.
在膜片钳记录的豚鼠心室肌细胞中，研究了β受体激动剂的作用以及腺苷酸环化酶刺激对钙电流和延迟整流钾通道离子电流的温度依赖性。我们报告，温度能够区分β受体介导的钾通道和钙通道调节。在19至32摄氏度范围内，受体介导的延迟整流钾电流增加而非钙电流增加对温度非常敏感。在室温（19 - 22摄氏度）下，β激动剂异丙肾上腺素使钙电流大幅增强，但对延迟整流电流无影响。相反，在较高温度（28 - 32摄氏度）下，激动剂存在时两种电流均增加。对于福斯可林直接刺激腺苷酸环化酶，这种温度敏感性也存在。因此，在肾上腺素能刺激过程中，心脏钙通道和钾通道似乎是独立调节的。
