Busch A E, Varnum M, Adelman J P, North R A
Vollum Institute, Oregon Health Sciences University, Portland 97201.
Biochem Biophys Res Commun. 1992 Apr 30;184(2):804-10. doi: 10.1016/0006-291x(92)90661-4.
A slowly activating potassium current was expressed in Xenopus oocytes by injection of RNA transcribed from a rat kidney cDNA clone. Hypotonic solutions (160 mOsmol/l; control was 220 mOsmol/l) increased the current by increasing the rate of activation and by decreasing the depolarization needed to activate the current. This effect of hypotonicity was not observed in calcium-free solution, but was unaffected by staurosporine or the calmodulin antagonist W7. Cytochalasin D reduced the current and prevented the increase by hypotonic solution. The results suggest that the increase in this potassium current by hypotonic solution might result from calcium entry and changes in the actin network.
通过注射从大鼠肾脏cDNA克隆转录而来的RNA，在非洲爪蟾卵母细胞中表达了一种缓慢激活的钾电流。低渗溶液（160毫渗摩尔/升；对照为220毫渗摩尔/升）通过提高激活速率和降低激活电流所需的去极化程度来增加电流。在无钙溶液中未观察到低渗的这种作用，但它不受星形孢菌素或钙调蛋白拮抗剂W7的影响。细胞松弛素D降低了电流并阻止了低渗溶液引起的电流增加。结果表明，低渗溶液引起的这种钾电流增加可能是由于钙内流和肌动蛋白网络的变化所致。
