Cholinergic Regulation of Resting Coronary Blood Flow in the Domestic Swine
Abstract
Neural factors have been proposed to mediate tonic contraction of coronary arteries and thereby limit coronary blood flow . Recently, acetylcholine was shown to mediate vasoconstriction of isolated vessels from several species, including man. The aims of the present studies in domestic swine were to demonstrate cholinergic vasoconstriction in vivo and to determine whether resting cholinergic activity mediates basal coronary tone. In either chronically instrumented or acute preparations, coronary blood flow, cardiac function and blood gases were measured during either acetylcholine injection, muscarinic receptor blockade, or vagal ligation. Intracoronary injections of acetylcholine (0.5 - 3.0 micro g) caused significant dose-dependent reductions (19-75%) in coronary flow and increases in coronary resistance. Atropine (200 micro g) completely blocked these responses. Cholinergic mediation of basal coronary tone was initially evaluating by determined the effects of muscarinic blockade with intracoronary injection of atropine. Intracoronary atropine significantly increased coronary flow and decreased resistance in closed-chest, sedated, non-paced pigs.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 17, 1989
- Accession Number
- ADA634909
Entities
People
- Conrad L. Cowan
Organizations
- Uniformed Services University of the Health Sciences