We are updating the design of this site. Learn more.
Show more
ClinicalTrials.gov
ClinicalTrials.gov Menu

Role of Endothelin in the Regulation of Vascular Tone in Patients With Essential Hypertension

This study has been completed.
Sponsor:
ClinicalTrials.gov Identifier:
NCT00001527
First Posted: December 10, 2002
Last Update Posted: March 4, 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 Institutes of Health Clinical Center (CC)
  Purpose

Endothelin-1 (ET-1) is a powerful vasoconstricting peptide produced predominantly by vascular endothelial cells, that exerts its effect through the interaction with specific receptors, ETA and ETB, on the underlying smooth muscle cells. Previous studies in normal subjects have demonstrated an increase in forearm blood flow after ET-1 antagonism, suggesting a physiologic role of ET-1 in the regulation of basal vascular tone. However, whether ET-1-mediated tone is increased in hypertensive patients is unknown.

The main purpose of this study will be to compare the forearm vascular responses to local infusion of ET-1 receptor antagonists between normotensive and hypertensive subjects in order to assess whether ET-1-mediated basal tone is increased in patients with hypertension. In addition, we propose to study the vascular responses to local ET-1 infusion to determine whether vascular smooth muscle sensitivity to this peptide is increased in hypertensive vessels. We will use both an ETA receptor antagonist, BQ-123, and an ETB receptor antagonist, BQ-788, in order to evaluate the relative contribution of the two receptor subtypes to the regulation of vascular tone.

All drugs will be infused into the brachial artery and the responses of the forearm vasculature will be measured by means of strain gauge plethysmography. Because of the relative long-lasting effect of most of the substances to be infused, the study will be performed on two separate occasions.


Condition
Hypertension

Study Type: Observational
Official Title: Role of Endothelin in the Regulation of Vascular Tone in Patients With Essential Hypertension

Further study details as provided by National Institutes of Health Clinical Center (CC):

Estimated Enrollment: 60
Study Start Date: November 1995
Estimated Study Completion Date: September 2000
Detailed Description:

Endothelin-1 (ET-1) is a powerful vasoconstricting peptide produced predominantly by vascular endothelial cells, that exerts its effect through the interaction with specific receptors, ETA and ETB, on the underlying smooth muscle cells. Previous studies in normal subjects have demonstrated an increase in forearm blood flow after ET-1 antagonism, suggesting a physiologic role of ET-1 in the regulation of basal vascular tone. However, whether ET-1-mediated tone is increased in hypertensive patients is unknown.

The main purpose of this study will be to compare the forearm vascular responses to local infusion of ET-1 receptor antagonists between normotensive and hypertensive subjects in order to assess whether ET-1-mediated basal tone is increased in patients with hypertension. In addition, we propose to study the vascular responses to local ET-1 infusion to determine whether vascular smooth muscle sensitivity to this peptide is increased in hypertensive vessels. We will use both an ETA receptor antagonist, BQ-123, and an ETB receptor antagonist, BQ-788, in order to evaluate the relative contribution of the two receptor subtypes to the regulation of vascular tone.

All drugs will be infused into the brachial artery and the responses of the forearm vasculature will be measured by means of strain gauge plethysmography. Because of the relative long-lasting effect of most of the substances to be infused, the study will be performed on two separate occasions.

  Eligibility

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.


Ages Eligible for Study:   Child, Adult, Senior
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Between 40-65 years old.

Normal Volunteers who are not taking medications. Have no medical problems. Cholesterol below 200 mg/dl. No contraceptives.

Hypertensive Patients with blood pressure greater than 145/90 off medications. Serum cholesterol less than 200 mg/dl. No other medical problems.

High cholesterol patients with cholesterol level greater than 250 mg/dl. No other medical problems.

  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): NCT00001527


Locations
United States, Maryland
National Heart, Lung and Blood Institute (NHLBI)
Bethesda, Maryland, United States, 20892
Sponsors and Collaborators
National Heart, Lung, and Blood Institute (NHLBI)
  More Information

Publications:
ClinicalTrials.gov Identifier: NCT00001527     History of Changes
Other Study ID Numbers: 960016
96-H-0016
First Submitted: November 3, 1999
First Posted: December 10, 2002
Last Update Posted: March 4, 2008
Last Verified: November 1999

Keywords provided by National Institutes of Health Clinical Center (CC):
BQ-123
BQ-788
Endothelin
Endothelium
Plethysmography
Essential Hypertension

Additional relevant MeSH terms:
Hypertension
Vascular Diseases
Cardiovascular Diseases