Counterbalance in functional adaptation to ureteral obstruction during development

Area of Science:

• Nephrology
• Developmental Biology
• Physiology

Background:

• Renal counterbalance describes compensatory kidney function after unilateral ureteral obstruction (UUO).
• Neonatal UUO in guinea pigs causes ipsilateral kidney vasoconstriction and growth arrest.
• The renin-angiotensin system plays a role in the hemodynamic response to UUO.

Purpose of the Study:

• To investigate the role of renal nerves and the renin-angiotensin system in renal counterbalance during neonatal UUO.
• To examine alterations in renin expression and localization in response to UUO.

Main Methods:

• Chronic partial UUO in neonatal guinea pigs and rats.
• Immunolocalization of renin.
• In situ hybridization for renin messenger RNA (mRNA).
• Northern blot analysis for renin mRNA.
• Chemical sympathectomy using guanethidine.

Main Results:

• UUO led to increased renin in juxtaglomerular apparatuses and afferent arterioles in both kidneys.
• Renin and renin mRNA levels were elevated in the obstructed kidney.
• Chemical sympathectomy reduced renin mRNA and prevented increased renin immunostaining.

Conclusions:

• Renal counterbalance in developing kidneys subjected to UUO is modulated by renal nerves.
• The response involves significant changes in renin gene expression and cellular processing.