Effects of Dobutamine on Left Ventricular Performance, Coronary Dynamics, and Distribution of Cardiac Output in Conscious Dogs

Abstract

The effects of dobutamine ([±] ¶4-[2- [[3-(p-hydroxyphenyl itg/kg/min, the drug increased dP/dt/P from 65±3 to 128i4 s' and isolength velocity from 72±4 to 120+7 mm/s without affecting LV end diastolic D significantly. Mean arterial P rose from 92±2 to 104±3 mm Hg and heart rate from 78±3 to 111+7 beats/min, while LV end systolic D fell from 24.1±+1.4 to 19.9±1.8 mm, reflecting a rise in stroke volume from 30±4 to 42±3 ml. Cardiac output rose from 2.41±0.23 to 4.35±0.28 liter/min, while calculated total peripheral resistance declined from 0.042+0.005 to 0.028±0.003 mm Hg/ml/min. The greatest increases in flow and decreases in calculated resistance occurred in the iliac and coronary beds, and the least occurred in the renal bed. Propranolol blocked the inotropic and betas dilator responses while vasoconstricting effects mediated by alpha adrenergic stimulation remained in each of the beds studied. When dobutamine was infused after a combination of practolol and phentolamine, dilatation occurred in each of the beds studied. These observations indicate that dobutamine is iDr.

Differential effects of (±)‐dobutamine and human α‐CGRP on cardiac and on regional haemodynamics in conscious Long Evans rats

“…This finding contrasts with those of the majority of previous studies in which administration of (±)-dobutamine caused no change (Vatner et al, 1974, boluses 1.6-8.Opmol kg-1, infusions 1.6pmol kg-' h-1; Robie & Goldberg, 1975, 0.4-6.4pmol kg-h-1; Leier et al, 1977Leier et al, , 1978.0jumol kg-1 h-1; Liang & Hood, 1979, 2-8pmol kg-1 h-1; Dorszewski et al, 1990, 0.2-0.8zmol kg-1 h-1) or an increase (Ruffolo & Messick, 1985b) in mean arterial blood pressure. However, these differences are likely to be due to differences in administered dose, since Biro .et al.…”

“…Under the same conditions, mesenteric and renal vascular conductances were either unchanged or, in the case of the latter during the higher dose infusion, reduced. While a relatively selective hindquarters vasodilator effect of (±)-dobutamine has been described previously (Vatner et al, 1974;Robie & Goldberg, 1975;Liang & Hood, 1979) this has not been observed invariably (Drexler et al, 1987;Biro et al, 1988), even in studies that did demonstrate a cerebral vasodilator response to (± )-dobutamine (Drexler et al, 1987). Although there was a greater hindquarters hyperaemia and a better maintenance of mesenteric blood flow during infusion of (+)-dobutamine than of human a-CGRP at either dose level, carotid hyperaemia was greater during infusion of the latter at the higher dose.…”

“…Thus, while a considerable literature on (±)-dobutamine exists, in large part it relates to bolus injections, brief infusions or incremental infusions of the drug (e.g. Vatner et al, 1974;Schoemaker, 1989;Dorszewski et al, 1990) often in anaesthetized or pithed animals (e.g. Robie & Goldberg, 1975;Ruffolo & Yaden, 1983;Ruffolo & Morgan, 1984;Maccarone et al, 1984;Ruffolo & Messick, 1985a,b;Biro et al, 1988).…”

Cardiovascular effects of dobutamine, dopamine and isoproterenol on the whole animal and isolated cross-perfused atrium in dogs.

“…administration of dobutamine to an intact animal produces a lesser increase in systemic blood pressure than that of dopamine (1,2). However, in isolated atria which were perfused with donor's blood, an i.v.…”

“…Indeed, dobutamine directly increases myocardial contractility without inducing marked tachycardia or greatly changing peripheral arterial resistance in intact dogs (1)(2)(3). In the cat papillary muscle, dobutamine increases the con tractility more but the automaticity less than did isoproterenol (1).…”