Cyclic AMP formation in Tetrahymena pyriformis is controlled by a K+‐conductance

FEBS Letters

Schultz, Joachim E.¹  Schönborn, Christof¹ 

[1] Universität Tübingen, Fakultät für Chemie und Pharmazie, Morgenstelle 8, D-72076 Tübingen, Germany

关键词: Tetrahymena;    K+ channel;    cAMP;    Hyperpolarization;   

DOI  :  10.1016/0014-5793(94)01300-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Responses of the cAMP generating system of Tetrahymena to changes in the concentrations of external [K⁺] or [Ca⁺] ions were examined. When Tetrahymena are equilibrated in high [K⁺] buffers, intracellular levels of cAMP decreased to 40% within 2 h. Hyperpolarization of the cells by dilution of external [K⁺] to one-eighth of its original concentration instantly stimulated intracellular cAMP formation. Manipulations of the K⁺ resting conductance of Tetrahymena by equilibration in buffers of different K⁺ content greatly affected the responsivity of the adenylyl cyclase. Hyperpolarization of the cell by addition of Ca²⁺ also resulted in a rapid generation of cAMP. Blockade of K⁺ conductances by the K⁺ channel blockers tetraethylammoniwn, quinine, and Cs⁺, dose-dependently inhibited hyperpolarization-stimulated cAMP formation. The data indicate that a hyperpolarization-activated K⁺ current is directly coupled to adenylyl cyclase regulation.

【 授权许可】

Unknown