The heterogeneity of ion channels in chromaffin granule membranes

Cellular & Molecular Biology Letters

Adam Szewczyk¹  Renata Hordejuk²  Krzysztof Dołowy² 

[1]Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093, Poland$$

[2]Department of Biophysics, Agriculture University SGGW, Warsaw, Poland$$

关键词: Chromaffin granule;    Intracellular channel;    Potassium channel;    Chloride channel;    Black lipid membrane;   

DOI  :  10.2478/s11658-006-0027-1

学科分类：分子生物学，细胞生物学和基因

来源: Uniwersytet Wroclawski * Wydzial Biotechnologii / University of Wroclaw, Faculty of Biotechnology

【 摘 要 】

Chromaffin granules are involved in catecholamine synthesis and traffic in the adrenal glands. The transporting membrane proteins of chromaffin granules play an important role in the ion homeostasis of these organelles. In this study, we characterized components of the electrogenic 86Rb+ flux observed in isolated chromaffin granules. In order to study single channel activity, chromaffin granules from the bovine adrenal medulla were incorporated into planar lipid bilayers. Four types of cationic channel were found, each with a different conductance. The unitary conductances of the potassium channels are 360 ± 10 pS, 220 ± 8 pS, 152 ± 8 pS and 13 ± 3 pS in a gradient of 450/150 mM KCl, pH 7.0. A multiconductance potassium channel with a conductivity of 110 ± 8 pS and 31 ± 4 pS was also found. With the exception of the 13 pS conductance channel, all are activated by depolarizing voltages. One type of chloride channel was also found. It has a unitary conductance of about 250 pS in a gradient of 500/150 mM KCl, pH 7.0.

【 授权许可】

Unknown