Journal article
Coronary microvascular response to exogenously administered and endogenously released acetylcholine
Microvascular research, Vol.43(3), pp.294-307
1992
DOI: 10.1016/0026-2862(92)90027-M
PMID: 1635474
Abstract
The objectives of the present study were first, to determine the coronary microvascular response to vagal stimulation and to compare it to exogenously administered acetylcholine, and second, to determine the microvascular response to larger doses of acetylcholine which preferentially increase subendocardial blood flow. In anesthetized cats and dogs, the left ventricular epicardial vasculature was visualized in mid-diastole with stroboscopic epi-illumination. Mycardial perfusion was measured with the radioactive microsphere technique. In cats microvascular diameters were measured at control and following bilateral vagal nerve stimulation (5–30 Hz) or left atrial infusion of acetylcholine (0.4–1.0 μg/kg/min). Aortic pressure and heart rate (
A-V—sequential pacing) were maintained constant. Vagal stimulation (
n = 13) increased myocardial perfusion by 25 ± 9% (control: 161 ± 17 ml/min · 100 g). Acetylcholine (
n = 13) produced a similar increase in myocardial flow (control: 185 ± 16 ml/min · 100 g, 30 ± 9%). Both vagal stimulation and acetylcholine dilated all size arteries and arterioles (51–410 μm; 5 ± 1% and 11 ± 2%, respectively). In dogs intracoronary administration of acetylcholine (10 μg/min) that increased myocardial flow twofold (control: 129 ± 7 ml/min · 100 g; 10 μg/min: 263 ± 26 ml/min · 100 g) and increased the endo/epi flow ratio also dilated all vessel sizes. In conclusion, vagal stimulation and exogenously administered acetylcholine produce similar effects on the coronary microcirculation and dilate all size classes of arteries and arterioles in a similar manner. Intracoronary infusion of acetylcholine which preferentially increases subendocardial blood flow also dilates all size classes of microvessels. Thus, the ability of acetylcholine to preferentially increase subendocardial blood flow cannot be explained by a selective dilation of a particular size class of arterioles. These data suggest that neurally released acetylcholine can diffuse to the endothelial layer to release vasodilator substances
in vivo.
Details
- Title: Subtitle
- Coronary microvascular response to exogenously administered and endogenously released acetylcholine
- Creators
- Kathryn G Lamping - The Department of Internal Medicine, College of Medicine, University of Iowa, Iowa City, Iowa 52242 USAWilliam M Chilian - The Department of Internal Medicine, College of Medicine, University of Iowa, Iowa City, Iowa 52242 USACharles L Eastham - The Department of Internal Medicine, College of Medicine, University of Iowa, Iowa City, Iowa 52242 USAMelvin L Marcus - The Department of Internal Medicine, College of Medicine, University of Iowa, Iowa City, Iowa 52242 USA
- Resource Type
- Journal article
- Publication Details
- Microvascular research, Vol.43(3), pp.294-307
- Publisher
- Elsevier Inc
- DOI
- 10.1016/0026-2862(92)90027-M
- PMID
- 1635474
- ISSN
- 0026-2862
- eISSN
- 1095-9319
- Language
- English
- Date published
- 1992
- Academic Unit
- Cardiovascular Medicine; Neuroscience and Pharmacology; Internal Medicine
- Record Identifier
- 9984094483002771
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