Schultz J E, Klumpp S, Benz R, Schürhoff-Goeters W J, Schmid A
Pharmazeutisches Institut, Universität Tübingen, Germany.
Science. 1992 Jan 31;255(5044):600-3. doi: 10.1126/science.1371017.
Hyperpolarization of the cell membrane of Paramecium stimulates adenosine 3',5'-monophosphate (cAMP) formation. Manipulations of the K+ resting conductance of the ciliate by adaptation in different buffers affected excitability of the cAMP generating system. Blockade of K+ channels inhibited hyperpolarization-stimulated cAMP formation. A mutant of Paramecium that is unable to control its K+ resting conductance had a defect in cAMP formation. Purified adenylyl cyclase, when incorporated into an artificial lipid bilayer membrane, revealed properties of a voltage-independent K+ channel. This indicates that the adenylyl cyclase of Paramecium has a secondary function as carrier of the K+ resting conductance. A hyperpolarization-activated K+ efflux appears to directly regulate adenylyl cyclase activity in vivo.
草履虫细胞膜的超极化刺激3',5'-环磷酸腺苷（cAMP）的形成。通过在不同缓冲液中适应来操纵纤毛虫的钾离子静息电导，会影响cAMP生成系统的兴奋性。钾离子通道的阻断抑制了超极化刺激的cAMP形成。一种无法控制其钾离子静息电导的草履虫突变体在cAMP形成方面存在缺陷。纯化的腺苷酸环化酶，当整合到人工脂质双分子层膜中时，显示出电压非依赖性钾离子通道的特性。这表明草履虫的腺苷酸环化酶具有作为钾离子静息电导载体的次要功能。超极化激活的钾离子外流似乎在体内直接调节腺苷酸环化酶的活性。
