Phasic vascular sodium pump changes in deoxycorticosterone-hypertensive rats

Area of Science:

• Cardiovascular Physiology
• Renal Physiology
• Endocrinology

Background:

• Deoxycorticosterone-salt (DOC-salt) administration is a model for studying hypertension.
• Vascular sodium pump (Na+/K+-ATPase) dysfunction is implicated in various hypertensive conditions.

Purpose of the Study:

• To investigate the time-dependent alterations in vascular sodium pump activity during DOC-salt-induced hypertension in rats.
• To correlate these changes with blood pressure, electrolyte balance, and overall health status.

Main Methods:

• Rats were treated with DOC and NaCl for varying durations (6-50 days).
• Vascular sodium pump activity was assessed via ouabain-sensitive 86Rb+ uptake.
• Systolic blood pressure, plasma electrolytes (Na+, K+), creatinine, and body weight were measured.

Main Results:

• Sodium pump activity was suppressed at day 6 (prehypertension), normalized by day 9, and increased at days 14 and 28 (hypertension).
• At 50 days, activity decreased, coinciding with a malignant state (low electrolytes, high creatinine, low body weight) and reduced blood pressure compared to 28-day hypertensive rats.
• Time-dependent changes in vascular sodium pump activity were observed throughout the hypertension model.

Conclusions:

• Vascular sodium pump activity exhibits dynamic, time-related changes during DOC-salt hypertension.
• The observed alterations in sodium pump activity may contribute to the development and progression of hypertension.
• A late-stage malignant state is characterized by suppressed sodium pump activity and distinct physiological derangements.