NCT00800228

Salt Study: Inhibited Breathing Pattern and Sodium Inhibitors in Sodium Sensitivity of Blood Pressure

Inhibited Breathing Pattern and Sodium Inhibitors in Sodium Sensitivity of Blood Pressure

• Status: Completed
• Phase: —
• Study type: Observational
• Enrollment: 96 (actual)
• Sponsor: National Institute on Aging (NIA) · NIH
• Sex: All
• Age: 40 Years – 70 Years
• Healthy volunteers: Accepted

Summary

The purpose of this study is to test the hypothesis that blood pressure sensitivity to high sodium intake in healthy humans is characterized by increased urinary excretion of two endogenous sodium pump inhibitors, marinobufagenin (MBG), and ouabain-like compound (OLC). The study also tests the hypothesis that women who breathe slowly and have high resting end tidal CO2 at rest are more likely to have low plasma renin activity and sodium sensitivity of blood pressure than those who breathe more rapidly and maintain lower end tidal CO2.

Detailed description

The experiments will involve a common procedure of sodium restriction followed by sodium loading of normotensive (having normal blood pressure) humans. However, the first experiment will involve continuous urine collection throughout the experimental period in a smaller group of men and women, while the second experiment will involve urine collection only at the end of each diet period in a larger group of normotensive women. If, as expected, experiment one shows that sodium loading produces MBG increases that are sustained throughout the sodium loading period, then experiment two will also be able to address a third issue: that is whether MBG or OLC response to sodium loading is specific to breathing pattern or sodium sensitivity. It is hypothesized that women with inhibited breathing who are sodium sensitive will show higher levels of MBG, even before sodium loading, but also following sodium loading. Each participant will be seen at the Clinical Research Unit for a screening visit and on days 6 and 12, and consume a low sodium diet for 6 days followed by a high sodium diet for 6 days. Research staff will meet with the participant at regular intervals for meal provision and transfer of 24-hr urine collections (if applicable). Respiration and blood pressure will be measured on the last day of each sodium diet.

Conditions

• Hypertension

Timeline

• Start date: 2003-03-01
• Primary completion: 2006-12-01
• Completion: 2006-12-01
• First posted: 2008-12-02
• Last updated: 2008-12-02

Locations

1 site across 1 country: United States