Positive inotropic effects mediated by alpha 1 adrenoceptors in intact human subjects.

Journal of Cardiovascular Pharmacology
R CurielL Cubeddu

Abstract

The role of alpha 1-adrenergic receptors (adrenoceptors) on cardiac contractility was investigated in human subjects. The effect of methoxamine, a selective alpha-adrenoceptor agonist, and angiotensin II, on cardiac contractility was determined by means of noninvasive assessment of the slope of the end-systolic pressure (ESP)/end-systolic dimension (ESD) relationship. The slope (m) of this ratio was significantly higher with methoxamine (17.0; SD = 9.0 mm Hg/mm) than with angiotensin II (4.8; SD = 1.9 mm Hg/mm) (p less than 0.05). Slopes with methoxamine were higher when heart rates (HRs) were reflexly reduced, and were significantly diminished when reflex bradycardia was prevented by atropine (p less than 0.05) or atrial pacing (p less than 0.01). Previous treatment with propranolol did not modify m values with methoxamine (m = 15.5; SD = 4.4 mm Hg/mm). Phentolamine, given at peak methoxamine effect, did not consistently modify m values, resulting in an average slope not significantly different from that obtained with methoxamine alone. However, the addition of phentolamine did not cause an increase in ESDs at each level of ESP with respect to methoxamine. In the same subjects, infusion of phentolamine after angiotensin did no...Continue Reading

Citations

Mar 1, 1992·British Journal of Clinical Pharmacology·M A Levine, F H Leenen
Sep 22, 2005·Clinical and Experimental Pharmacology & Physiology·Roberto CurielMiguel Cerrolaza
May 1, 1992·Circulation·R Curiel, J F Pérez-González
Apr 27, 2011·Anesthesia and Analgesia·Robert H ThieleCarl Lynch
Apr 27, 2011·Anesthesia and Analgesia·Robert H ThieleCarl Lynch
Sep 29, 2018·Journal of Clinical Monitoring and Computing·Karin H WodackDaniel A Reuter
Apr 28, 1993·European Journal of Pharmacology·J Pepke-ZabaT Kealey

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