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Ontogenic changes in renal response to alpha 1-adrenoceptor stimulation in sheep. Am J Physiol 1994 Oct;267(4 Pt 2):R990-8

Date

10/01/1994

Pubmed ID

7943440

DOI

10.1152/ajpregu.1994.267.4.R990

Scopus ID

2-s2.0-0028115462   9 Citations

Abstract

The present study was designed to examine the effect of direct intrarenal infusion of the alpha 1-adrenoceptor agonist, phenylephrine, on urinary flow rate (UFR) and on renal Na and Cl excretion in conscious and chronically instrumented fetal (128-133 days gestation, term 145 days), newborn (6-12 days), and adult sheep. Five different renal concentrations of phenylephrine, varying from 5 +/- 1 to 72 +/- 2 ng/ml, were studied. Low renal phenylephrine concentration (< or = 12 +/- 1 ng/ml) induced a significant renal vasoconstrictor response in fetuses but not in newborn and adult sheep. The effects of intrarenal phenylephrine infusion on UFR and fractional excretion of Na (FENa) was greater (P < 0.05) in newborn lambs than in fetal and adult sheep. At a renal concentration of phenylephrine between 9 +/- 1 and 12 +/- 1 ng/ml, the percent decrease in UFR was greater (P < 0.05) in newborn lambs (-19.1 +/- 4.7%) than in fetal (9.8 +/- 8.9%) and adult sheep (-3.3 +/- 3.9). The percent decrease in FENa at renal concentration of phenylephrine between 18 +/- 1 and 24 +/- 1 ng/ml was also significantly (P < 0.05) larger in newborn lambs (-20.2 +/- 2.8%) than in fetal (-8.0 +/- 3.1%) and adult sheep (-11.2 +/- 2.6%). In summary, the present results indicate that the fetal kidney has a limited ability to increase sodium reabsorption in response to stimulation of alpha-adrenoceptors and that the effect of renal alpha-adrenoceptor stimulation on urinary volume and urinary sodium excretion increases during the newborn period.

Author List

Guillery EN, Segar JL, Merrill DC, Nakamura KT, Jose PA, Robillard JE

Author

Jeffrey L. Segar MD Professor in the Pediatrics department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Aging
Animals
Animals, Newborn
Blood Pressure
Chlorides
Dose-Response Relationship, Drug
Embryonic and Fetal Development
Female
Gestational Age
Glomerular Filtration Rate
Heart Rate
Heart Rate, Fetal
Infusions, Intravenous
Kidney
Norepinephrine
Phenylephrine
Pregnancy
Receptors, Adrenergic, alpha-1
Reference Values
Renal Circulation
Sheep
Sodium
Urine
Vasoconstriction
jenkins-FCD Prod-399 190a069c593fb5498b7fcd942f44b7bc9cdc7ea1