Dopamine-1 receptor stimulation impairs intestinal oxygen utilization during critical hypoperfusion.
Effects of a dopamine-1 (DA-1) receptor agonist on systemic and intestinal oxygen delivery (Do(2))-uptake relationships were studied in anesthetized dogs during sequential hemorrhage. Control (group 1) and experimental animals (group 2) were treated similarly except for the addition of fenoldopam (1.0 microg x kg(-1) x min(-1)) in group 2. Both groups had comparable systemic critical Do(2) (Do(2crit)), but animals in group 2 had a higher gut Do(2crit) (1.12 +/- 1.13 vs. 0.80 +/- 0.09 ml. kg(-1) x min(-1), P < 0.05). At the mucosal level, a clear biphasic delivery-uptake relationship was not observed in group 1; thus oxygen consumption by the mucosa may be supply dependent under physiological conditions. Group 2 demonstrated higher peak mucosal blood flow and lack of supply dependency at higher mucosal Do(2) levels. Fenoldopam resulted in a more conspicuous biphasic relationship at the mucosa and a rightward shift of overall splanchnic Do(2crit) despite increased splanchnic blood flow. These findings suggest that DA-1 receptor stimulation results in increased gut perfusion heterogeneity and maldistribution of perfusion, resulting in increased susceptibility to ischemia.
Guzman
Jorge A
JA
Division of Pulmonary, Critical Care, and Sleep Medicine, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.
Rosado
Ariosto E
AE
Kruse
James A
JA
D000818:Animals; D001682:Biological Availability; D004285:Dogs; D018818:Fenoldopam / Q000494:pharmacology; D007413:Intestinal Mucosa / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects; D017447:Receptors, Dopamine D1 / Q000378:metabolism*; D013152:Splanchnic Circulation / Q000187:drug effects
D017447:Receptors, Dopamine D1; D018818:Fenoldopam; D010100:Oxygen