Gambierol Blocks a K+ Current Fraction without Affecting Catecholamine Release in Rat Fetal Adrenomedullary Cultured Chromaffin Cells

Evelyne Benoit, Sébastien Schlumberger, Jordi Molgó, Makoto Sasaki, Haruhiko Fuwa, Roland Bournaud

研究成果: ジャーナルへの寄稿学術論文査読

1 被引用数 (Scopus)

抄録

Gambierol inhibits voltage-gated K+ (KV) channels in various excitable and non-excitable cells. The purpose of this work was to study the effects of gambierol on single rat fetal (F19–F20) adrenomedullary cultured chromaffin cells. These excitable cells have different types of KV channels and release catecholamines. Perforated whole-cell voltage-clamp recordings revealed that gambierol (100 nM) blocked only a fraction of the total outward K+ current and slowed the kinetics of K+ current activation. The use of selective channel blockers disclosed that gambierol did not affect calcium-activated K+ (KCa) and ATP-sensitive K+ (KATP) channels. The gambierol concentration necessary to inhibit 50% of the K+ current-component sensitive to the polyether (IC50) was 5.8 nM. Simultaneous whole-cell current-clamp and single-cell amperometry recordings revealed that gambierol did not modify the membrane potential following 11s depolarizing current-steps, in both quiescent and active cells displaying repetitive firing of action potentials, and it did not increase the number of exocytotic catecholamine release events, with respect to controls. The subsequent addition of apamin and iberiotoxin, which selectively block the KCa channels, both depolarized the membrane and enhanced by 2.7 and 3.5-fold the exocytotic event frequency in quiescent and active cells, respectively. These results highlight the important modulatory role played by KCa channels in the control of exocytosis from fetal (F19–F20) adrenomedullary chromaffin cells.

本文言語英語
論文番号254
ジャーナルToxins
14
4
DOI
出版ステータス出版済み - 2022 4月

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