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Seitelberger R, Guth BD, Heusch G, et al. Alpha 2-adrenergic coronary constriction in ischemic myocardium during exercise. Basic Res Cardiol. 1990;85:207-17doi: 10.1007/978-3-662-11038-6_17.
Seitelberger, R., Guth, B. D., Heusch, G., & Ross, J. (1990). Alpha 2-adrenergic coronary constriction in ischemic myocardium during exercise. Basic research in cardiology, 85207-17. https://doi.org/10.1007/978-3-662-11038-6_17
Seitelberger, R, et al. "Alpha 2-adrenergic coronary constriction in ischemic myocardium during exercise." Basic research in cardiology vol. 85 (1990): 207-17. doi: https://doi.org/10.1007/978-3-662-11038-6_17
Seitelberger R, Guth BD, Heusch G, Ross J. Alpha 2-adrenergic coronary constriction in ischemic myocardium during exercise. Basic Res Cardiol. 1990;85:207-17. doi: 10.1007/978-3-662-11038-6_17. PMID: 1982609.
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Basic Res Cardiol. 1990;85:207-17. doi: 10.1007/978-3-662-11038-6_17.

Alpha 2-adrenergic coronary constriction in ischemic myocardium during exercise.

Basic research in cardiology

R Seitelberger, B D Guth, G Heusch, J Ross

Affiliations

  1. Seaweed Canyon Laboratory, Department of Medicine, University of California, San Diego, School of Medicine.

PMID: 1982609 DOI: 10.1007/978-3-662-11038-6_17

Abstract

The effect of either selective alpha 1- or alpha 2-adrenoceptor blockade on ischemic myocardial blood flow and function was examined in beta-blocked dogs trained to run on a motor-driven treadmill. The animals were instrumented with sonomicrometers for the assessment of regional systolic wall thickening (%WTh) of the left ventricle. For drug infusion, an intracoronary catheter was implanted in the circumflex coronary artery and a hydraulic cuff was placed proximally around the artery. Following systemic beta-blockade with 0.8 mg/kg propranolol, an acute stenosis of the circumflex coronary artery inflated during exercise induced severe dysfunction in the posterior wall. Intracoronary infusion of 80 micrograms/kg of the selective alpha 2-adrenoceptor blocking agent idazoxan improved posterior wall (PW)-%WTh from 5.1 +/- 1.6 to 10.8 +/- 2.8% (p less than 0.06) and regional myocardial blood flow (radiolabelled microspheres) in the subendocardium of the posterior wall from 0.17 +/- 0.05 to 0.45 +/- 0.30 (ml/min)/g (p less than 0.05). No increases in regional blood flow and regional myocardial function were observed after infusion of the selective alpha 1-adrenoceptor blocking agent prazosin (20 micrograms/kg) under the same experimental conditions. It is concluded that during severe ischemia, significant postjunctional alpha 2-adrenoceptor mediated coronary vasoconstriction exists. Regional alpha 2-adrenoceptor blockade, but not alpha 1-adrenoceptor blockade is effective in reducing regional ischemia and dysfunction by attenuating sympathetic vasoconstriction in the conscious dog.

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