Effect of brief myocardial ischemia on sympathetic coronary vasoconstriction. Circ Res 1992 Oct;71(4):960-9
Date
10/01/1992Pubmed ID
1516166DOI
10.1161/01.res.71.4.960Scopus ID
2-s2.0-0026808796 (requires institutional sign-in at Scopus site) 30 CitationsAbstract
The purpose of the present study was to determine whether sympathetic coronary vasoconstrictor responses are altered after brief ischemia and reperfusion. Adult mongrel dogs were anesthetized and instrumented for measurements of heart rate, arterial pressure, left ventricular pressure, left ventricular dP/dt, anterior myocardial wall thickening, and left circumflex coronary artery (LCX) and left anterior descending coronary artery (LAD) blood flow velocities. Changes in coronary vascular resistance were recorded during intravenous bolus doses of norepinephrine and bilateral electrical stimulation of the stellate ganglia. After beta-adrenergic blockade and bilateral vagotomy, electrical stimulation of the stellate ganglia increased coronary vascular resistance in the LAD and LCX beds by 38 +/- 5% and 39 +/- 5%, respectively. After a 15-minute LAD occlusion, repeat electrical stimulation produced increases in coronary resistance of 16 +/- 3% and 45 +/- 8%, respectively (p less than 0.05 for the LAD before versus after the occlusion). The peak increase in coronary vascular resistance to two doses of norepinephrine was unchanged. After a shorter period of myocardial ischemia (7 minutes), similar increase in coronary resistance to stellate stimulation were observed before (27 +/- 4%) and after (26 +/- 6%) myocardial ischemia. The mechanism of this impaired sympathetic coronary vasoconstriction was further tested by examining the responses to bretylium and tyramine. Brief ischemia did not alter the coronary constrictor responses to either bretylium or tyramine, suggesting that mechanisms governing prejunctional release of norepinephrine are intact in the postischemic coronary arterial bed.(ABSTRACT TRUNCATED AT 250 WORDS)
Author List
Gutterman DD, Morgan DA, Miller FJMESH terms used to index this publication - Major topics in bold
AnimalsBretylium Compounds
Coronary Circulation
Coronary Vessels
Dogs
Female
Hemodynamics
In Vitro Techniques
Male
Norepinephrine
Reperfusion Injury
Sympathetic Nervous System
Time Factors
Tyramine
Vascular Resistance
Vasoconstriction