Do prostaglandins modulate renal haemodynamic effects of endothelin-1 in conscious lambs?
To test the hypothesis that vasodilatory prostaglandins buffer the renal vasoconstrictor effects of endothelin-1 (ET-1) early in life, renal haemodynamic responses to ET-1 were measured in 2 groups of conscious, chronically instrumented lambs at 1-2 weeks of age (group I, n = 11) and 6 weeks of age (group II, n = 10). Lambs were pretreated with vehicle or 1 mg x kg(-1) indomethacin, a nonselective cyclooxygenase inhibitor, and renal haemodynamic effects were measured continuously for 1 min before (control) and 5 min after intra-arterial injection of 250 ng x kg(-1) ET-1. In group II lambs, there was a marked decrease in renal blood flow (RBF) and renal vascular conductance (RVC) elicited by ET-1 administration, as we have previously described. This response was not altered by vehicle or indomethacin pretreatment. In group I lambs, there was an initial increase but no decrease in RBF and RVC elicited by ET-1 administration, as we have previously described, and this response was also not altered by either vehicle or indomethacin. These results suggest that endogenously produced prostaglandins do not appear to modulate the renal haemodynamic effects of ET-1 in conscious lambs during postnatal maturation.
Department of Physiology & Biophysics, Faculty of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada.
Kumar Kesavarao
KK
Ebenezar
Fatemah Ghane
FG
Sharbaf
Wei
W
Qi
Francine Gabriel
FG
Smith
D000818:Animals; D000831:Animals, Newborn; D003243:Consciousness / Q000187:drug effects* / Q000502:physiology; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D019332:Endothelin-1 / Q000494:pharmacology* / Q000502:physiology*; D005260:Female; D006439:Hemodynamics / Q000187:drug effects / Q000502:physiology; D007668:Kidney / Q000098:blood supply* / Q000187:drug effects / Q000502:physiology; D008297:Male; D011453:Prostaglandins / Q000502:physiology*; D012079:Renal Circulation / Q000187:drug effects* / Q000502:physiology; D012756:Sheep
D016861:Cyclooxygenase Inhibitors; D019332:Endothelin-1; D011453:Prostaglandins