Dopamine in Orthostatic Tolerance

One goal of this study is to determine whether people with different amounts of dopamine-beta-hydroxylase (DBH) have different responses to events that affect blood pressure and heart rate. We will also study whether increasing dietary salt improves symptoms during upright posture. Finally, we will examine whether the dietary sodium level influences serum DBH activity and whether DBH level influences the response to sodium. DBH levels and the function of the sympathetic or involuntary nervous system will be assessed in normal volunteers and in patients with postural tachycardia syndrome (POTS).

Study Overview

• Status: Terminated
• Conditions: Postural Tachycardia Syndrome
• Intervention / Treatment: Dietary supplement: dietary sodium; Dietary supplement: dietary sodium; Dietary supplement: dietary sodium

• Study Type: Interventional
• Enrollment (Actual): 22
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Tennessee
    • Nashville, Tennessee, United States, 37232
      • Vanderbilt University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 60 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Upright plasma norepinephrine > 600 pg/ml, or
• An increase in heart rate of > 30 beats per minute upon standing, and
• Withdrawal of all medications for at least 3 days, and
• No associated medical illness, and
• Age 18 - 60 years old.

Exclusion Criteria:

• Older than 60 years of age
• Routinely taking medications affecting the autonomic nervous system
• Any chronic illness (cardiac, pulmonary, endocrine, gastrointestinal, rheumatologic) other than POTS
• Anemia (Hct < 30)
• Women of childbearing age who are pregnant or nursing
• Unable to give informed consent

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: A; 10 mEq/day dietary sodium	Dietary supplement: dietary sodium; 10 mEq/day; Dietary supplement: dietary sodium; 300 mEq/day; Dietary supplement: dietary sodium; 150 mEq/day dietary sodium
Experimental: B; 150 mEq/day dietary sodium	Dietary supplement: dietary sodium; 10 mEq/day; Dietary supplement: dietary sodium; 300 mEq/day; Dietary supplement: dietary sodium; 150 mEq/day dietary sodium
Experimental: C; 300 mEq/day dietary sodium	Dietary supplement: dietary sodium; 10 mEq/day; Dietary supplement: dietary sodium; 300 mEq/day; Dietary supplement: dietary sodium; 150 mEq/day dietary sodium

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
plasma dopamine-beta-hydroxylase	at enrollment and after tests
plasma dopamine	after tests

Collaborators and Investigators

• Sponsor: Vanderbilt University
• Investigators: Principal Investigator: Emily M Garland, PhD, Vanderbilt University

Study record dates

Study Major Dates

• Study Start: November 1, 2004
• Primary Completion (Actual): July 1, 2012
• Study Completion (Actual): July 1, 2012

Study Registration Dates

• First Submitted: September 5, 2008
• First Submitted That Met QC Criteria: September 5, 2008
• First Posted (Estimate): September 8, 2008

Study Record Updates

• Last Update Posted (Estimate): June 15, 2015
• Last Update Submitted That Met QC Criteria: June 11, 2015
• Last Verified: June 1, 2015

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pathologic Processes; Heart Diseases; Cardiovascular Diseases; Nervous System Diseases; Arrhythmias, Cardiac; Cardiac Conduction System Disease; Autonomic Nervous System Diseases; Primary Dysautonomias; Orthostatic Intolerance; Tachycardia; Postural Orthostatic Tachycardia Syndrome
• Other Study ID Numbers: 040769; HL071784