Endothelin B receptor-deficient mice develop endothelial dysfunction independently of salt loading

Area of Science:

• Cardiovascular Physiology
• Endocrinology
• Hypertension Research

Background:

• Endothelin B (ETB) receptor deficiency in rodents is linked to salt-sensitive hypertension.
• The precise mechanisms underlying this hypertension remain unclear.
• ETB receptors influence endothelial nitric oxide and prostacyclin synthesis, impacting endothelial function.

Purpose of the Study:

• To investigate the effect of a salt-enriched diet on endothelial function in rescued ETB receptor-deficient mice.
• To determine if endothelial dysfunction contributes to salt-induced hypertension in this model.

Main Methods:

• Rescued ETB receptor-deficient mice and wild-type controls were fed standard (0.2% NaCl) or high-salt (4% NaCl) diets for 15 days.
• Systolic blood pressure was measured using the tail cuff method.
• Endothelium-dependent and independent vascular functions were assessed in isolated aortic rings.

Main Results:

• ETB receptor-deficient mice on a high-salt diet exhibited increased systolic blood pressure (166 mmHg) compared to wild-type mice (128 mmHg).
• Endothelium-dependent relaxation was impaired in ETB receptor-deficient mice (74%) versus wild-type (96%), irrespective of diet.
• Endothelium-independent relaxation and endothelin-1 contractions were not significantly altered by diet or ETB receptor blockade.

Conclusions:

• Rescued ETB receptor-deficient mice develop salt-sensitive hypertension.
• Endothelial dysfunction in this model is present independently of salt-enriched diet or hypertension.
• Salt-induced hypertension in this ETB receptor deficiency model is not mediated by endothelial dysfunction.