Renal Salt Handling in Postural Tachycardia Syndrome Following Dietary Dopa Administration

2014-08-27 03:16:03 | BioPortfolio


The purpose of this study is to learn how plants can play a role in gain/loss of sodium in the urine and in the regulation of blood pressure. Dopamine is a chemical mostly present in the brain and kidneys which assists in regulation of the body's salts (sodium and potassium). Fava beans contain a lot of the chemical that increases the production of dopamine by the kidneys.

The purpose of these studies is to characterize the diuretic effects of dietary catecholamine sources in both healthy individuals and in patients with POTS. Specific aims are:

1. To determine the effect of dietary dopa sources on plasma and urinary catecholamines.

2. To investigate the capacity of botanical dopaminergic agents (fava beans) to induce natriuresis in a short term study.

3. To provide preliminary data on the effects of dietary dopa on heart rate and blood pressure regulation in POTS patients.

4. To compare responses in patients with POTS with those of healthy volunteers.

In these studies, we will test the null hypothesis (Ho) that the effect of dietary dopa on urinary sodium excretion will not differ between patients with POTS and healthy volunteers.


Postural tachycardia syndrome (POTS) is the most common form of orthostatic intolerance, affecting an estimated 500,000 Americans, principally young women. POTS refers to an excessive increase in heart rate (>30 beats per minute) on standing in the absence of orthostatic hypotension. Patients typically experience symptoms of excessive sympathetic activation with physical or emotional exertion. POTS can produce substantial disability among otherwise healthy people.Previous findings by the Robinson/Garland research group suggest that mechanisms involved in orthostatic and absolute volume regulation contribute to POTS pathophysiology. We have preliminary data showing that patients with POTS do not decrease urinary sodium excretion after 30-60 minutes of upright posture, whereas healthy control subjects do. The following studies are designed to determine the effects of food sources of dopa and dopamine on plasma and urine catecholamine levels and to characterize their diuretic effects. We will compare the influences of diet in patients with POTS and healthy volunteers. Davidson previously reported an increase in plasma dopamine levels within one hour of consuming a banana{Davidson, 1981}. Kema described an increase in urinary catecholamine metabolites two hours after consumption of a dopamine-enriched meal{Kema, 1992}. The results of our studies may indicate that consumption of foods with high dopa content stimulates natriuresis and may suggest that foods such as bananas and/or fava beans could serve as a potential adjunctive therapy for patients who require a diuretic.

Study Design

Endpoint Classification: Safety/Efficacy Study, Intervention Model: Parallel Assignment, Masking: Open Label, Primary Purpose: Basic Science


Postural Tachycardia Syndrome


Fava beans


Vanderbilt University Clinical Research Centerb
United States




Vanderbilt University

Results (where available)

View Results


Published on BioPortfolio: 2014-08-27T03:16:03-0400

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