Abnormal platelet function and calcium handling in Dahl salt-hypertensive rats

Area of Science:

• Cardiovascular Physiology
• Cellular Biology
• Hypertension Research

Background:

• Dietary salt intake is a major factor in hypertension development.
• Platelet function and calcium (Ca2+) homeostasis are crucial in cardiovascular health.
• Dahl salt-sensitive (DS) rats are a genetic model for studying salt-induced hypertension.

Purpose of the Study:

• To investigate the impact of a high-salt diet on platelet function and Ca2+ homeostasis in DS rats.
• To determine if salt-induced alterations in platelet Ca2+ handling are linked to hypertension.
• To explore the role of nitric oxide in modulating platelet Ca2+ dynamics under high-salt conditions.

Main Methods:

• DS rats were fed high-salt (DSHS) or low-salt (DSLS) diets for up to 4 weeks.
• Systolic blood pressure, platelet P-selectin expression, and intracellular Ca2+ stores were measured.
• Platelet Ca2+ influx, sarcoplasmic/endoplasmic Ca2+ ATPase activity, and nitric oxide effects were analyzed.

Main Results:

• High-salt diet increased blood pressure and significantly elevated ionomycin-releasable Ca2+ in platelet stores (Ca2+/IM).
• Increased Ca2+ store filling and sarcoplasmic/endoplasmic Ca2+ ATPase activity were observed in DSHS rats.
• Thrombin-induced Ca2+ influx and agonist-induced P-selectin expression decreased in DSHS rats, with impaired nitric oxide-mediated Ca2+ store reuptake.

Conclusions:

• High-salt diet in DS rats enhances sarcoplasmic/endoplasmic Ca2+ ATPase activity and Ca2+ store capacity.
• Altered intracellular Ca2+ handling in platelets may explain decreased Ca2+ influx and P-selectin expression.
• These salt-induced platelet changes are potentially heritable and contribute to salt-sensitive hypertension.