Published in:
01-11-2005 | Original Article
Nitric oxide modulates renal vasoconstrictor effect of endothelin-1 in conscious lambs
Authors:
Francine G. Smith, Liesbeth van der Velde, Alp Sener
Published in:
Pediatric Nephrology
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Issue 11/2005
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Abstract
To test the hypothesis that nitric oxide (NO) buffers the renal vasoconstrictor effects of endothelin-1 (ET-1) early in life, renal haemodynamic responses to ET-1 were measured in the presence and absence of endogenously produced NO in conscious lambs. Renal haemodynamic effects of ET-1 were measured for 5 min before (control) and 20 min after intraarterial injection of ET-1 before and after pretreatment with 20 mg/kg of the l-arginine analogue NG-nitro-l-arginine methyl ester (l-NAME), (experiment 1) and its inactive isomer D-NAME (experiment 2) in conscious lambs aged ~1 week (N=7) and ~6 weeks (N=6). The two experiments were carried out in random order at intervals of 24–48 h. In lambs aged ~6 weeks, a marked increase in renal vascular resistance (RVR) was elicited by ET-1 administration; this response was enhanced twofold following pretreatment with l-NAME. In 1-week-old lambs, however, an increase in RVR in response to ET-1 occurred only after pretreatment with l-NAME. Therefore, we accept our hypothesis and conclude that NO buffers the renal vasoconstrictor effects of ET-1 early in life.