Abstract
There is evidence for a critical role of the interaction between endogenous Endothelium. Derived Relaxing Factor or Nitric Oxdide (NO) and Angiotensin II (Ang II) in the control of adult renal hemodynamics. This study was designed to explore if such NO-Ang II interaction exists in the isolated developing rabbit kidney, perfused in presence of indomethacin 10. μmol/l and to see how such interaction evolves with renal maturation.
Results: In rabbits with a postnatal age of 7 and 20 days, it was shown that under control conditions vasoconstrictory responses to low concentrations of Ang II (10−10 mol/L) decrease with kidney age from 15,8% to 8,9%, whereas responses to high concentrations of Ang II (10−8 mol/L); increase with kidney development from 32,3% to 55,6%. Competitive inhibition of NO synthase by nitro-L-arginine methyl ester (L-NAME) (100 μmol/L) augmented, vasoconstrictory responses to 10−10 mol/L Ang II by about 80% in kidneys of both 7 and 20 days. In both cases, L-arginine (substrate of NO synthase), was able to reverse the effect of L-NAME. At both ages, the effect of L-NAME on 10−8 mol/L Ang II was markedly more discrete. In conclusion, 1) the developing kidney does exhibit an Ang II-NO interaction, which is related to a low concentration of Ang II and appears to be stronger earlier in the process of nephrogenesis. 2) Since vasoconstrictory responses to high conc. of Ang II increased and vasoconstrictory responses to low conc. of Ang II decreased with age, developmental changes in the vasoconstrictory and NO-dependent vasodilatory component of Ang II action appear to evolve differently during nephrogenesis (a developmental change in relative attribution of different AT receptor subtypes may perhaps be involved in both phenomena).
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Van Zwet, J., Simeoni, U. & Helwig, JJ. 260 VASCULAR RESPONSES IN THE NEONATAL ISOLATED PERFUSED RABBIT KIDNEY: INTERACTIONS BETWEEN ANGIOTENSIN II AND NITRIC OXIDE. Pediatr Res 36, 46 (1994). https://doi.org/10.1203/00006450-199407000-00260
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DOI: https://doi.org/10.1203/00006450-199407000-00260
