Quinine inhibits Ca2+‐independent K+ channels whereas tetraethylammonium inhibits Ca2+‐activated K+ channels in insulin‐secreting cells

FEBS Letters

Ullrich, Susanne¹  Wollheim, Claes B.¹  Petersen, Ole H.¹  Dunne, Mark J.¹  Findlay, Ian¹ 

[1] MRC Secretory Control Research Group, The Physiological laboratory, University of Liverpool, PO Box 147, Brownlow Hill, Liverpool L69 3BX, England

关键词: RINm5F cell;    Patch clamp;    K+ channel;    Tetraethylammonium;    Quinine;   

DOI  :  10.1016/0014-5793(85)80729-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The effects of quinine and tetraethylammonium (TEA) on single-channel K⁺ currents recorded from excised membrane patches of the insulin-secreting cell line RINm5F were investigated. When 100 μM quinine was applied to the external membrane surface K⁺ current flow through inward rectifier channels was abolished, while a separate voltage-activated high-conductance K⁺ channel was not significantly affected. On the other hand, 2 mM TEA abolished current flow through voltage-activated high-conductance K⁺ channels without influencing the inward rectifier K⁺ channel. Quinine is therefore not a specific inhibitor of Ca²⁺-activated K⁺ channels, but instead a good blocker of the Ca²⁺-independent K⁺ inward rectifier channel whereas TEA specifically inhibits the high-conductance voltage-activated K⁺ channel which is also Ca²⁺-activated.

【 授权许可】

Unknown