Hemodynamic effects of dobutamine in an intact animal model.
METHODS
Actions of dobutamine at the beta 1, beta 2, and alpha 1 adrenoreceptors were studied in anesthetized dogs. Six animals received dobutamine (at infusion rates of 0 to 160 micrograms/kg/min) with and without beta-adrenergic receptor blockade. Five animals received phenylephrine (0 to 16 micrograms/kg/min), with and without concurrent dobutamine (20 micrograms/kg/min); this procedure was repeated in five animals after beta-blockade.


RESULTS
Dobutamine (10 to 160 micrograms/kg/min) increased heart rate (HR), cardiac output, and left ventricular change in pressure over time, and decreased systemic vascular resistance. beta-blockade prevented only dobutamine-induced changes in HR. Mean arterial pressure (MAP), unaffected by dobutamine alone, decreased with concurrent beta-blockade. Phenylephrine (1 to 16 micrograms/kg/min)-induced increases in MAP were unaffected by dobutamine; with beta-blockade, phenylephrine reduced MAP. Dobutamine prevented a phenylephrine-induced increase in systemic vascular resistance, an effect eliminated by beta-adrenergic receptor blockade.


CONCLUSIONS
Dobutamine appeared to be an agonist at the beta 1- and beta 2-adrenoreceptors and at the myocardial alpha-adrenoreceptor. Dobutamine appeared to be an alpha-adrenergic receptor antagonist in the peripheral vasculature.
Department of Pediatrics, University of Utah School of Medicine, Salt Lake City.
D D
DD
Vernon
J S
JS
Garrett
W
W
Banner
J M
JM
Dean
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D004280:Dobutamine / Q000494:pharmacology*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005260:Female; D006439:Hemodynamics / Q000187:drug effects*; D008297:Male; D010656:Phenylephrine / Q000494:pharmacology; D011412:Propanolamines / Q000494:pharmacology; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects; D011943:Receptors, Adrenergic, beta / Q000187:drug effects*
D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D010656:Phenylephrine; D004280:Dobutamine; C036604:esmolol