Apamin‐sensitive potassium channels mediate agonist‐induced oscillations of membrane potential in pituitary gonadotrophs

FEBS Letters

Stojilković, Stanko S.²  Kukuljan, Manuel¹  Catt, Kevin J.²  Rojas, Eduardo¹ 

[1] Laboratory of Cell Biology and Genetics, National Institute of Diabetes, Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA;Endocrinology and Reproduction Research Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA

关键词: Pituitary;    Intracellular Ca2+;    Ca2+ channel;    Ca2+-sensitive K+ channel;    GnRH;    gonadotropin-releasing hormone;    VSCC;    voltage-sensitive Ca2+ channels;    V m;    membrane potential;    AP;    action potentials;   

DOI  :  10.1016/0014-5793(92)80201-Q

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

In cultured rat pituitary gonadotrophs, gonadotropin-releasing hormone (GnRH) induces rapid hyperpolarization of the cell membrane and causes cessation of the spontaneous electrical activity present in non-stimulated cells. This initial response to GnRH is followed by slow oscillations of membrane potential (V _m) which often exhibit brief bursts of action potentials (AP) fired from the peak of the oscillations. The hyperpolarization waves are synchronous with GnRH-induced elevations of cytoplasmic Ca²⁺ concentration ([Ca₂₊]_i), such that V _m maxima alternate with the peak values of [Ca²⁺]_i. The V _m oscillations result from repetitive activation of apamin-sensitive K⁺ channels by cytoplasmic Ca²⁺. Thus, GnRH activation of Ca²⁺ mobilization can generate a bursting pattern of membrane potential through the activation of K⁺ channels against a background of spontaneous electrical activity.

【 授权许可】

Unknown