Journal article
Response of coronary microvascular collaterals to activation of ATP-sensitive K+ channels
Cardiovascular research, Vol.35(2), pp.377-383
1997
DOI: 10.1016/S0008-6363(97)00112-0
PMID: 9349401
Abstract
Objective: Studies have suggested that collateral vessels of the coronary and hind-limb circulations are more sensitive to activation of ATP-sensitive K+ channels than are non-collateral vessels. The objective of the present study was to compare responses of microvascular non-collaterals, native collaterals and stimulated collaterals in the heart to three vasodilators which act through different mechanisms: activation of ATP-sensitive K+ channels with aprikalim, release of nitric oxide with acetylcholine, and endothelium-independent activation of soluble guanylate cyclase with nitroglycerin.
Methods: Collateral growth was stimulated by placing an Ameroid occluder on the proximal left circumflex artery in dogs. Non-collaterals, native collaterals and stimulated collaterals (100-220 microns in diameter) were isolated, cannulated on micropipettes and pressurized in vitro. Vessel diameters were measured using videomicroscopy.
Results: Dilation to aprikalim (10(-8)-10(-5) M), acetylcholine (10(-9)-10(-6) M) and nitroglycerin (10(-8)-3 x 10(-4) M) were similar in non-collateral, native collateral and stimulated collaterals. Dilation of native collaterals to aprikalim and acetylcholine was attenuated by glibenclamide (10 microM), an inhibitor of ATP-sensitive K+ channels, but not by tetraethylammonium (1 mM), a non-selective inhibitor of K+ channels. Dilation of native collaterals to acetylcholine but not aprikalim was also inhibited by nitro-L-arginine (10 microM), an inhibitor of nitric oxide synthase.
Conclusion: These findings suggest that microvascular native and stimulated collaterals respond to activation of ATP-sensitive K+ channels and acetylcholine similar to non-collaterals of similar size. Thus, changes in reactivity of collaterals to activation of ATP-sensitive K+ channels are not related to changes in the ability of the vessels to respond to vasodilators but may primarily be determined by a change in the distribution of collateral vessel size.
Details
- Title: Subtitle
- Response of coronary microvascular collaterals to activation of ATP-sensitive K+ channels
- Creators
- Kathryn G Lamping - Department of Internal Medicine and The Cardiovascular Center, College of Medicine, University of Iowa, E314-4 GH, Iowa City, IA 52242, United StatesDaniel W Nuno - Department of Internal Medicine and The Cardiovascular Center, College of Medicine, University of Iowa, E314-4 GH, Iowa City, IA 52242, United StatesLeonard A Brooks - Department of Internal Medicine and The Cardiovascular Center, College of Medicine, University of Iowa, E314-4 GH, Iowa City, IA 52242, United StatesMikio Fujii - Department of Internal Medicine and The Cardiovascular Center, College of Medicine, University of Iowa, E314-4 GH, Iowa City, IA 52242, United States
- Resource Type
- Journal article
- Publication Details
- Cardiovascular research, Vol.35(2), pp.377-383
- Publisher
- Oxford University Press
- DOI
- 10.1016/S0008-6363(97)00112-0
- PMID
- 9349401
- ISSN
- 0008-6363
- eISSN
- 1755-3245
- Language
- English
- Date published
- 1997
- Academic Unit
- Cardiovascular Medicine; Surgery; Neuroscience and Pharmacology; Cardiothoracic Surgery; Internal Medicine
- Record Identifier
- 9984094622702771
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