Kleinhaus A L, Zeman R J
Department of Cell Biology and Anatomy, New York Medical College, Valhalla 10595.
Brain Res. 1994 Jul 11;650(2):326-30. doi: 10.1016/0006-8993(94)91800-7.
Elevation of [K+]o for 30 s from 4 to 120 mM produced a fast and reversible depolarization and transient increase in [Ca2+]i in fura-2 loaded Retzius cells of the leech. The protein phosphatase inhibitor, okadaic acid, significantly slowed the return of [Ca2+]i toward baseline without affecting the amplitude of depolarization or rate of repolarization. Furthermore, okadaic acid and another phosphatase inhibitor, calyculin A, prolonged Ba(2+)-dependent action potentials. These results suggest that the kinetics of Ca2+ influx may be regulated by the activity of phosphatases PP-1 and/or PP-2A.
将[K⁺]ₒ从4 mM升高至120 mM持续30秒，可使水蛭中经fura - 2加载的Retzius细胞快速且可逆地去极化，并使[Ca²⁺]ᵢ短暂增加。蛋白磷酸酶抑制剂冈田酸显著减慢了[Ca²⁺]ᵢ恢复至基线的速度，而不影响去极化幅度或复极化速率。此外，冈田酸和另一种磷酸酶抑制剂花萼海绵诱癌素A延长了Ba²⁺依赖性动作电位。这些结果表明，Ca²⁺内流的动力学可能受磷酸酶PP - 1和/或PP - 2A的活性调节。
