KIR channels function as electrical amplifiers in rat vascular smooth muscle

P D Smith; S E Brett; K D Luykenaar; Shaun L Sandow; S P Marrelli; E J Vigmond; D G Welsh

doi:10.1113/jphysiol.2007.145474

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KIR channels function as electrical amplifiers in rat vascular smooth muscle

Journal article

Peer reviewed

KIR channels function as electrical amplifiers in rat vascular smooth muscle

P D Smith, S E Brett, K D Luykenaar, Shaun L Sandow, S P Marrelli, E J Vigmond and D G Welsh

Journal of Physiology, Vol.586(4), pp.1147-1160

2008

DOI: https://doi.org/10.1113/jphysiol.2007.145474

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Abstract

vascular smooth muscle

KIR channels function

Strong inward rectifying K+ (KIR) channels have been observed in vascular smooth muscle and can display negative slope conductance. In principle, this biophysical characteristic could enable KIR channels to 'amplify' responses initiated by other K+ conductances. To test this, we have characterized the diversity of smooth muscle KIR properties in resistance arteries, confirmed the presence of negative slope conductance and then determined whether KIR inhibition alters the responsiveness of middle cerebral, coronary septal and third-order mesenteric arteries to K+ channel activators. Our initial characterization revealed that smooth muscle KIR channels were highly expressed in cerebral and coronary, but not mesenteric arteries. These channels comprised KIR 2.1 and 2.2 subunits and electrophysiological recordings demonstrated that they display negative slope conductance. Computational modelling predicted that a KIR-like current could amplify the hyperpolarization and dilatation initiated by a vascular K+ conductance. This prediction was consistent with experimental observations which showed that 30 μ m Ba2+ attenuated the ability of K+ channel activators to dilate cerebral and coronary arteries. This attenuation was absent in mesenteric arteries where smooth muscle KIR channels were poorly expressed. In summary, smooth muscle KIR expression varies among resistance arteries and when channel are expressed, their negative slope conductance amplifies responses initiated by smooth muscle and endothelial K+ conductances. These findings highlight the fact that the subtle biophysical properties of KIR have a substantive, albeit indirect, role in enabling agonists to alter the electrical state of a multilayered artery. © 2008 The Authors. Journal compilation © 2008 The Physiological Society.

Details

Title: KIR channels function as electrical amplifiers in rat vascular smooth muscle
Authors: P D Smith (Author) - University of Calgary, Canada
S E Brett (Author) - University of Calgary, Canada
K D Luykenaar (Author) - University of Calgary, Canada
Shaun L Sandow (Author) - University of New South Wales
S P Marrelli (Author) - Baylor College of Medicine, United States
E J Vigmond (Author) - University of Calgary, Canada
D G Welsh (Author) - University of Calgary, Canada
Publication details: Journal of Physiology, Vol.586(4), pp.1147-1160
Publisher: Wiley-Blackwell Publishing Ltd.
Date published: 2008
DOI: 10.1113/jphysiol.2007.145474
ISSN: 0022-3751
Organisation Unit: School of Health - Biomedicine; University of the Sunshine Coast, Queensland; School of Health and Sport Sciences - Legacy; School of Health and Behavioural Sciences - Legacy
Language: English
Record Identifier: 99448957202621
Output Type: Journal article

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Collaboration types: Domestic collaboration; International collaboration
Web Of Science research areas: Neurosciences; Physiology

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