Suzuki K
Department of Bio-Medical Engineering, School of High-Technology for Human Welfare, Tokai University, Numazu Shizuoka, Japan.
Tokai J Exp Clin Med. 1995 Dec;20(4-6):195-201.
The effects of adenosine 3', 5'-cyclic monophosphate (cAMP)-dependent protein phosphorylation on Ca(2+)-sensitivity of Ca(2+)-dependent K(+)-channels in guinea-pig pancreatic acinar cells were studied by patch-clamp single-channel methods. When opening of the channels did not occur in excised inside-out membrane patches exposed to 10(-6) M Ca2+, the addition of 25 U/ml catalytic units of cAMP-dependent protein kinase (PKA) to the bath solution opened the channels, with a conductance of 30 pS (in symmetrical K(+)-rich solution). The addition of a PKA-inhibitor (100 microM) extinguished the PKA-dependent opening of the K(+)-channels. Alkaline phosphatase (5 U/ml) reversed the PKA-dependent opening of the K(+)-channels to control levels (before PKA). These results demonstrate that cAMP-dependent protein phosphorylation initiates the Ca(2+)-sensitivity of the Ca(2+)-dependent K(+)-channels in guinea-pig pancreatic acinar cells.
采用膜片钳单通道方法研究了3',5'-环磷酸腺苷（cAMP）依赖性蛋白磷酸化对豚鼠胰腺腺泡细胞中钙依赖性钾通道钙敏感性的影响。当暴露于10(-6) M Ca2+的内面向外膜片未出现通道开放时，向浴液中添加25 U/ml的cAMP依赖性蛋白激酶（PKA）催化单位可使通道开放，电导为30 pS（在富含钾的对称溶液中）。添加PKA抑制剂（100 microM）可消除PKA依赖性的钾通道开放。碱性磷酸酶（5 U/ml）可使PKA依赖性的钾通道开放恢复到对照水平（PKA处理前）。这些结果表明，cAMP依赖性蛋白磷酸化引发了豚鼠胰腺腺泡细胞中钙依赖性钾通道的钙敏感性。
