Watanabe K, Funase K
Department of Physiology, Gifu University School of Medicine, Japan.
Neurosci Res. 1991 Feb;10(1):64-70. doi: 10.1016/0168-0102(91)90020-y.
The involvement of protein phosphorylation in cAMP-induced transmembrane current was tested electrophysiologically and pharmacologically in identified neurons of the Japanese land snail, Euhadra peliomphala. Intracellular injection of cAMP elicited a biphasic transmembrane current (cAMP current) which consisted of inward and outward components. The inward component was blocked with Na(+)-free, Ca2(+)-free saline and the outward component abolished by either application of tetraethylammonium or a long-lasting exposure to caffeine in Ca2(+)-free saline. The cAMP current was completely suppressed by the protein kinase inhibitors, protein kinase inhibitor isolated from rabbit muscle or isoquinoline sulfonamide (H-8). The catalytic subunit of cAMP-dependent protein kinase transiently restored the cAMP current suppressed by H-8 nearly to pre-H-8 level. These findings suggest that protein phosphorylation may be an intermediate step in the activation process of the cAMP current.
通过电生理学和药理学方法，在日本陆地蜗牛（Euhadra peliomphala）的特定神经元中检测了蛋白质磷酸化在环磷酸腺苷（cAMP）诱导的跨膜电流中的作用。向细胞内注射cAMP会引发双相跨膜电流（cAMP电流），该电流由内向和外向成分组成。内向成分在无钠、无钙盐溶液中被阻断，外向成分在应用四乙铵或在无钙盐溶液中长时间暴露于咖啡因后被消除。蛋白激酶抑制剂、从兔肌肉中分离出的蛋白激酶抑制剂或异喹啉磺酰胺（H-8）可完全抑制cAMP电流。环磷酸腺苷依赖性蛋白激酶的催化亚基可将被H-8抑制的cAMP电流短暂恢复至接近H-8处理前的水平。这些发现表明，蛋白质磷酸化可能是cAMP电流激活过程中的一个中间步骤。
