Dopamine-1 receptor stimulation attenuates the vasoconstrictive response to gut ischemia.
The effects of fenoldopam, a dopamine-1 (DA-1) receptor agonist, were studied in two groups of anesthetized dogs before and after induction of splanchnic ischemia by way of hemorrhage. During the first portion of the experiment, both groups received fenoldopam (1.5 microg x kg(-1) x min(-1)) for 45 min followed by a 45-min washout. During the second portion, hemorrhage (10 ml/kg) was induced, followed by no intervention in group I (controls) and restarting of the fenoldopam infusion in group II. Prehemorrhage, fenoldopam increased composite portal blood flow by 33% (P < 0.01). After hemorrhage-induced splanchnic ischemia, fenoldopam restored portal vein blood flow to near baseline, maintained the splanchnic fraction of cardiac output, and attenuated the rise in gut mucosal PCO(2). DA-1 receptor stimulation increased portal blood flow and redistributed blood flow away from the serosal layer in favor of the mucosa during basal conditions and after hemorrhage, suggesting a more concentrated distribution of splanchnic DA-1 receptors within the mucosal layer vasculature. Fenoldopam maintained splanchnic blood flow during hypoperfusion and attenuated the splanchnic vasoconstrictive response to hemorrhage.
Guzman
J A
JA
Division of Pulmonary, Critical Care, and Sleep Medicine, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.
Rosado
A E
AE
Kruse
J A
JA
D000818:Animals; D001794:Blood Pressure; D002302:Cardiac Output; D004285:Dogs; D018491:Dopamine Agonists / Q000494:pharmacology; D018818:Fenoldopam / Q000494:pharmacology*; D006339:Heart Rate; D006439:Hemodynamics / Q000187:drug effects / Q000502:physiology*; D006470:Hemorrhage; D007413:Intestinal Mucosa / Q000098:blood supply / Q000502:physiology*; D007422:Intestines / Q000098:blood supply; D007511:Ischemia / Q000503:physiopathology*; D007773:Lactates / Q000097:blood; D008099:Liver / Q000098:blood supply; D011168:Portal System / Q000187:drug effects / Q000502:physiology*; D017447:Receptors, Dopamine D1 / Q000187:drug effects / Q000502:physiology*; D012039:Regional Blood Flow / Q000187:drug effects; D013152:Splanchnic Circulation / Q000187:drug effects / Q000502:physiology*; D014655:Vascular Resistance; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology*
D018491:Dopamine Agonists; D007773:Lactates; D017447:Receptors, Dopamine D1; D018818:Fenoldopam