Aberrant ENaC activation in Dahl salt-sensitive rats

Area of Science:

• Nephrology
• Cardiovascular Physiology
• Molecular Biology

Background:

• The epithelial sodium channel (ENaC) is crucial for regulating blood pressure via kidney sodium reabsorption.
• Dahl salt-sensitive rats exhibit hypertension on high-salt diets, with abnormal ENaC mRNA expression despite low aldosterone.

Purpose of the Study:

• To investigate the impact of high-salt diet on ENaC protein expression in rat models.
• To evaluate the therapeutic effects of amiloride and eplerenone on hypertension and kidney injury in Dahl salt-sensitive rats.

Main Methods:

• Comparative analysis of ENaC protein expression in Dahl salt-resistant and salt-sensitive rats under high-salt conditions.
• Treatment of Dahl salt-sensitive rats with amiloride or eplerenone during high-salt diet exposure.
• Assessment of blood pressure and renal damage markers.

Main Results:

• High-salt diet induced hypertension and renal damage in Dahl salt-sensitive rats.
• Despite suppressed aldosterone, beta and gammaENaC mRNA and protein levels increased, with enhanced gammaENaC activation.
• Amiloride, but not eplerenone, significantly improved blood pressure and reduced kidney injury, indicating aldosterone-independent ENaC activation.

Conclusions:

• Inappropriate ENaC expression and activation contribute to salt-sensitive hypertension and organ damage in Dahl rats.
• Amiloride shows therapeutic potential for salt-sensitive hypertension characterized by excessive ENaC activity.