Renal effects of low to moderate doses of dopamine in newborn piglets.
OBJECTIVE
Administration of dopamine to adult animal and human subjects results in increased renal blood flow, and it may also enhance the glomerular filtration rate. However, renal hemodynamic effects of exogenous dopamine in the neonate are unclear. In this study, we examined the renal actions of low to moderate doses of exogenous dopamine in newborn piglets.


METHODS
The animals were anesthetized, catheterized for vascular access and urine collection, and assigned randomly to a control group or treatment groups receiving dopamine infusion at 2, 5, or 10 microg/kg/min. Data were collected at baseline, during dopamine infusion, and 1 hour after cessation of infusion. Mean arterial blood pressure (MAP) and heart rate (HR) were monitored. Glomerular filtration rate (GFR), cardiac index (CI), and renal blood flow (RBF) were determined. Fractional excretion of sodium (FENa) was calculated.


RESULTS
Dopamine did not alter renal blood flow nor did it significantly alter CI in spite of a modest increase in heart rate and mean arterial blood pressure. There was a statistically significant increase in GFR at 10 microg/kg/min and in FENa at all doses.


CONCLUSIONS
Low doses of dopamine produce significant natriuresis probably by direct action on renal tubules and at moderate doses via, both, increase in GFR and a direct tubular effect. Low and moderate doses of dopamine do not increase RBF as seen in adult animals, possibly because of immaturity of dopaminergic receptors in newborn piglets.
Division of Pediatric Surgery, University of Illinois College of Medicine at Chicago, 60016, USA.
L B
LB
Nguyen
G
G
Lievano
J
J
Radhakrishnan
L C
LC
Fornell
G
G
Jacobson
E G
EG
John
D000818:Animals; D000831:Animals, Newborn; D004298:Dopamine / Q000008:administration & dosage / Q000494:pharmacology*; D005919:Glomerular Filtration Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D007668:Kidney / Q000098:blood supply / Q000187:drug effects*; D009318:Natriuresis / Q000187:drug effects; D011954:Receptors, Dopamine / Q000187:drug effects; D012039:Regional Blood Flow / Q000187:drug effects; D013552:Swine; D014655:Vascular Resistance / Q000187:drug effects; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000494:pharmacology*
D011954:Receptors, Dopamine; D014665:Vasodilator Agents; D004298:Dopamine