Salt-sensitive hypertension in bradykinin B2 receptor knockout mice

Area of Science:

• Physiology
• Cardiovascular Research
• Renal Physiology

Background:

• The kallikrein-kinin system is crucial for blood pressure (BP) homeostasis by regulating water and sodium excretion.
• Bradykinin, acting via the B2 receptor, is a key component of this system.

Purpose of the Study:

• To investigate the role of the bradykinin B2 receptor in salt-sensitive hypertension.
• To determine if B2 receptor deficiency exacerbates the hypertensive response to high sodium intake.

Main Methods:

• Comparison of blood pressure responses to high sodium diet in wild-type and B2 receptor knockout (B2-KO) mice.
• Assessment of organ weights (heart, kidney) to evaluate hypertensive effects.
• Dose-response curves for vasoactive substances (bradykinin, acetylcholine, angiotensin II) in both groups.

Main Results:

• B2-KO mice exhibited a nearly doubled hypertensive response to high sodium intake compared to controls.
• High sodium diet increased heart and kidney weight in B2-KO mice, indicating increased afterload.
• The BP response to bradykinin was abolished in B2-KO mice, while responses to acetylcholine and angiotensin II were preserved.

Conclusions:

• Mice lacking the bradykinin B2 receptor present a novel model of salt-sensitive hypertension.
• Kinins, through the B2 receptor, appear to play a protective role against salt-induced hypertension in mice.