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Forearm Vascular Relaxation

This study has been completed.
ClinicalTrials.gov Identifier:
First Posted: September 16, 2005
Last Update Posted: August 29, 2008
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
Information provided by:
National Institute on Aging (NIA)
The purpose of this study is to learn the effect of inherited differences on forearm blood flow responses to hormones and drugs


Study Type: Observational
Study Design: Time Perspective: Prospective
Official Title: Determinants of Forearm Vascular Relaxation: Role of Genetic Polymorphisms

Further study details as provided by National Institute on Aging (NIA):

Estimated Enrollment: 400
Study Start Date: May 2003
Study Completion Date: December 2006
Primary Completion Date: December 2006 (Final data collection date for primary outcome measure)
Detailed Description:
Differences in at least 4 genes are believed to have an important effect on responses to hormones and drugs. For this study, healthy volunteers of normal body weight will be screened to find xxx individuals with the genes of interest. Very small doses of hormones and drugs will be given so that changes in forearm blood flow can be measured, while not causing effects throughout the body. A brachial artery line and venous line will be placed in the study arm so that blood samples may be withdrawn to compare amounts given into the artery and coming out of the vein after circulating through the arm. Forearm blood flow is determined by the rate of swelling of the arm after a blood pressure cuff is inflated (above venous and below arterial blood pressure). The hormones and drugs being studied include angiotensin I, angiotensin II, acetylcholine, sodium nitroprusside, enalaprilat, L-arginine, phenylephrine, endothelin-1, verapamil, and isoproterenol. This procedure will last 4-6 hours. The process will be repeated with the same participant over 2 weeks later.

Information from the National Library of Medicine

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Ages Eligible for Study:   21 Years to 45 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Normal physical status without any medical interventions or agents which would alter the defined status of normal

Exclusion Criteria:

  • Age less than 21 or greater than 45
  • Unable to give informed consent
  • BMI (Body Mass Index) less than 18 or greater than 25
  • Clinically significant abnormal laboratory values
  • Abnormal physical exam
  • Abnormal EKG
  • Pregnancy
  • Smoking or drug usage (illicit or otherwise)
  • Post-menopause
  • Participation in another clinical trial in the past month
  • Chronic Illness
  Contacts and Locations
Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00182923

United States, Maryland
National Institute on Aging (NIA), Harbor Hospital
Baltimore, Maryland, United States, 21225
Sponsors and Collaborators
National Institute on Aging (NIA)
Principal Investigator: Darrell R. Abernethy, MD, PhD National Institute on Aging, Laboratory of Clinical Investigation