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Endogenous bradykinin regulates renal function in the newborn rabbit
1Service de Pédiatrie, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland. jean-pierre.guignard@chuv.hospvd.ch
Biology of the Neonate
|May 9, 1998
Summary
The neonatal kidney's kallikrein-kinin system (KKS) regulates blood flow by dilating efferent arterioles. Blocking bradykinin receptors in newborn rabbits revealed KKS's role in immature kidney hemodynamics.
Area of Science:
- Nephrology
- Physiology
- Pharmacology
Background:
- The renal kallikrein-kinin system (KKS) undergoes developmental changes linked to neonatal kidney hemodynamics.
- Understanding the KKS's functional role in the developing kidney is crucial.
Purpose of the Study:
- To investigate the effect of the bradykinin B2 receptor antagonist HOE-140 on the neonatal kidney.
- To clarify the functional importance of the renal KKS in the immature kidney.
Main Methods:
- Administration of HOE-140, a bradykinin B2 receptor antagonist, to newborn rabbits.
- Measurement of renal vascular resistance, renal blood flow, glomerular filtration rate, urine flow, and electrolyte excretion.
Main Results:
- HOE-140 administration increased renal vascular resistance and decreased renal blood flow.
- Glomerular filtration rate remained unchanged, but filtration fraction increased, indicating efferent arteriolar constriction.
- Urine flow and fractional potassium excretion increased, while sodium excretion was unaffected.
Conclusions:
- The renal KKS plays a regulatory role in the immature kidney under basal conditions.
- The KKS promotes efferent arteriolar vasodilation, regulating neonatal glomerular microcirculation.
- This contrasts with the mature kidney, where KKS primarily acts as a diuretic-natriuretic factor on tubular function.