PMID: 7085431Apr 1, 1982Paper

Hemodynamic responses to methoxamine in exercise-conditioned and aorta-constricted rats

Journal of Applied Physiology: Respiratory, Environmental and Exercise Physiology
E M HasserJ L Haithcoat

Abstract

Hemodynamic responses to methoxamine hydrochloride (Vasoxyl) were determined in rats conditioned by a moderate treadmill exercise program and in rats subjected to 5 wk of abdominal aortic constriction. Rats of comparable age served as controls. Initial hemodynamic values for control rats were as follows: left ventricular pressure, 124 +/- 4 Torr and cardiac index, 145 +/- 8 ml . min-1 . kg-1. Although minor variations were noted, initial hemodynamic values for exercise-conditioned rats were within the normal range, and no left ventricular hypertrophy was present. Aorta-constricted rats exhibited a 50% increase in left ventricular weight and significant differences in left ventricular pressure (173 +/- 9 Torr) and cardiac index (117 +/- 10 ml . min-1 . kg-1). Sequentially increasing doses of methoxamine were infused to elevate myocardial preload and afterload. When compared with control rats, exercise-conditioned animals were better able to maintain cardiac index at comparable increases in either mean arterial or left ventricular end-diastolic pressures. In contrast, aorta-constricted rats demonstrated profound reductions in hemodynamic functions in response to methoxamine infusion. Directionally divergent hemodynamic results oc...Continue Reading

Citations

May 18, 2001·American Journal of Physiology. Heart and Circulatory Physiology·P J FadelP B Raven

Related Concepts

Ascending Aorta Structure
Diastolic Blood Pressure
Cardiac Output
Closure by Clamp
Diastole
Pulse Rate
Hemodynamics
Metoxamine Wellcome
August Rats
Ventricular Function

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