K+ currents in human coronary artery vascular smooth muscle cells

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Item Type:	Article
Title:	K+ currents in human coronary artery vascular smooth muscle cells
Creators Name:	Gollasch, M., Ried, C., Bychkov, R., Luft, F.C. and Haller, H.
Abstract:	K+ channels and their currents are important in vascular tone regulation and are potential therapeutic targets; however, K+ channels in human coronary artery vascular smooth muscle cells (VSMCs) have received little attention. We examined K+ currents in freshly isolated VSMCs from human coronary arteries (n=368 from 32 human hearts) with conventional patch-clamp or perforated-patch techniques with nystatin. We detected four different K+ currents: (1) the delayed rectifier K+ current, IK(dr); (2) the Ca2+-activated K+ current, IK(Ca); (3) the nonrectifying noninactivating outward ATP-dependent K+ current, IK(ATP); and (4) the spontaneous transient outward K+ current, IK(STOC). K+ channels underlying spontaneous transient outward currents probably represent a single clustered population of Ca2+-activated K+ channels functionally associated with Ca2+ release channels in the sarcoplasmic reticulum. Inwardly rectifying K+ currents were not observed. K+ currents were unevenly distributed in that they were not uniformly exhibited by all cells. The most prominent K+ currents were IK(Ca) (100%) and IK(dr) (46%). IK(STOC)s, which have not been previously described in humans, were present in 67% of VSMCs. IK(ATP) was small under physiological conditions; however, IK(ATP) increased markedly after cell stimulation with exogenous or endogenous coronary vasodilators. Thus, IK(ATP) may be particularly relevant in ischemia and could be of special importance as a therapeutic target. We conclude that human coronary VSMCs have unique K+ currents that differ sufficiently from those of other species, thus making the investigation of human material clinically relevant. The findings suggest potential avenues for further therapeutic research.
Keywords:	K+ Channels, Delayed Rectifier Current, Transient Outward Current, K+ Channel Openers, Pituitary Adenylate Cyclase-Activating Peptide
Source:	Circulation Research
ISSN:	0009-7330
Publisher:	American Heart Association
Volume:	78
Number:	4
Page Range:	676-688
Date:	April 1996
Official Publication:	http://circres.ahajournals.org/cgi/content/abstract/78/4/676
PubMed:	View item in PubMed

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