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CO2-dependent opening of an inwardly rectifying K+ channel

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Huckstepp, Robert T. R. and Dale, Nicholas. (2011) CO2-dependent opening of an inwardly rectifying K+ channel. Pfluegers Archiv, Vol.461 (No.3). pp. 337-344. ISSN 0031-6768

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Official URL: http://dx.doi.org/10.1007/s00424-010-0916-z

Abstract

CO2 chemosensing is a vital function for the maintenance of life that helps to control acid–base balance. Most studies have reported that CO2 is measured via its proxy, pH. Here we report an inwardly rectifying channel, in outside-out excised patches from HeLa cells that was sensitive to modest changes in PCO2 under conditions of constant extracellular pH. As PCO2 increased, the open probability of the channel increased. The single-channel currents had a conductance of 6.7 pS and a reversal potential of –70 mV, which lay between the K+ and Cl– equilibrium potentials. This reversal potential was shifted by +61 mV following a tenfold increase in extracellular [K+] but was insensitive to variations of extracellular [Cl–]. The single-channel conductance increased with extracellular [K+]. We propose that this channel is a member of the Kir family. In addition to this K+ channel, we found that many of the excised patches also contained a conductance carried via a Cl–-selective channel. This CO2-sensitive Kir channel may hyperpolarize excitable cells and provides a potential mechanism for CO2-dependent inhibition during hypercapnia.

Item Type:	Journal Article
Subjects:	Q Science > QP Physiology
Divisions:	Faculty of Science > Life Sciences (2010- )
Library of Congress Subject Headings (LCSH):	Chemical senses, Carbon dioxide, Blood gases, Biological control systems
Journal or Publication Title:	Pfluegers Archiv
Publisher:	Springer
ISSN:	0031-6768
Date:	14 January 2011
Volume:	Vol.461
Number:	No.3
Page Range:	pp. 337-344
Identification Number:	10.1007/s00424-010-0916-z
Status:	Peer Reviewed
Access rights to Published version:	Open Access
Funder:	Biotechnology and Biological Sciences Research Council (Great Britain) (BBSRC), Medical Research Council (Great Britain) (MRC)
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URI:	http://wrap.warwick.ac.uk/id/eprint/34583