Brief vagal stimulation during partial coronary constriction induces sustained decreases in coronary blood flow and excitation of afferent cardiac sympathetic nerve fibers mediated by adrenergic alpha-receptors.
Answers are grounded in this paper and cite their sources.
May provoke ischemia during partial constriction via alpha-receptors; leaves open relevance to human vagal maneuvers or CAD.
The effect of vagal stimulation on activity of afferent sympathetic nerve fibers from the dog's left ventricle has been examined. During partial constriction of the coronary artery, a brief electrical stimulation of the cervical vagus nerves resulted in a decrease in blood flow of the constricted artery, systolic bulge of the left ventricle, elevation of the ST segment of electrocardiogram and excitation of the afferent nerve fibers, which continued for up to 15 min. These changes were not produced without coronary artery constriction. Intravenous injection of phentolamine eliminated the decrease in blood flow, and suppressed systolic bulge, elevation of the ST segment and excitation of afferent fibers. Propranolol could not eliminate the decrease in blood flow while suppressed the other changes. Atropine eliminated all of these changes. The results indicate participation of adrenergic alpha-receptors in sustained decrease of coronary blood flow and excitation of afferent cardiac sympathetic nerve fibers which can be produced by a brief vagal excitation.
No takes yet. Share an insight, caveat, or question.
Uchida et al. (1975) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: