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Quantitative analysis of single K+ channels in the tonoplast of Chara corallina: selectivity and TEA blockade.

par Fuks, Bruno ;Homblé, Fabrice
Référence Journal of plant physiology, 137, 6, page (729-733)
Publication Publié, 1991

Article révisé par les pairs

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Résumé :

Patch-clamp measurements were made on the tonoplast surrounding protoplasmic droplets using the inside-out configuration. Three channels with different unitary conductance were observed in symmetrical 150 mM KCl. Two of them are highly selective to K+ and have an unitary conductance of 132 and 89 pS. The selectivity sequence of the 132 PS K+ channel for monovalent cations was: K ? Cs ? Rb ? Na. The mechanism of TEA blockade was investigated on both sides of the 132 pS K+ channel. Our results suggest the presence of two different binding sites for TEA in the channel. This block was voltage-dependent when TEA was added to the bath but not when it was added to the pipette. © 1991, Gustav Fischer Verlag, Stuttgart. All rights reserved.