Role of Prostaglandins in the Regulation of Brain Blood Flow

March 3, 2008 updated by: National Institutes of Health Clinical Center (CC)

Role of Prostaglandins in the Control of Cerebral Blood Flow During Hypercapnia and Functional Activation in Humans

This study will use magnetic resonance imaging (MRI) to examine the role of prostaglandins-a type of fatty acid with hormone-like actions-in the regulation of brain blood flow. The results will provide information on how to better use this technique to study brain function, which, in turn, may lead to a better understanding of certain illnesses and more effective treatments.

Healthy normal volunteers 18 years of age and older may be eligible for this study. Participants will fill out a health questionnaire and undergo a history, physical examination and MRI studies. MRI is a diagnostic tool that uses a strong magnetic field and radio waves instead of X-rays to show structural and chemical changes in tissues. During the scanning, the subject lies on a table in a narrow cylinder containing a magnetic field. An intercom system allows the subject to speak with the staff member performing the study at all times during the procedure. Four separate studies will be done-two carbon dioxide inhalation studies and two functional activation studies-as follows:

Carbon dioxide inhalation (indomethacin): This study is done in two parts. In both parts, an MRI brain scan is done. During the scan, the subject inhales an air mixture containing 6% carbon dioxide through a facemask or mouthpiece. Blood pressure and heart rate are monitored during inhalation of the mixture. For the second part of the study, indomethacin-a non-steroidal anti-inflammatory drug-is injected through a catheter (thin flexible tube) in an arm vein. Indomethacin inhibits prostaglandin production. Total scan time averages between 45 and 90 minutes, with a maximum of 2 hours.

Carbon dioxide inhalation (rofecoxib and celecoxib): This study is identical to the one above, except either rofecoxib or celecoxib is given instead of indomethacin. Both of these drugs are also non-steroidal anti-inflammatory drugs that inhibit prostaglandin production. Unlike indomethacin, rofecoxib and celecoxib are given orally instead of through a vein, so, to allow time for the drug to be absorbed, the second scan is delayed for 2 hours.

Functional activation (indomethacin): This study is done in two parts. In both parts, a MRI brain scan is done. During the study, the subject performs a simple motor task, such as finger tapping. For the second part of the study, indomethacin is injected through a catheter in an arm vein.

Functional activation (rofecoxib and celecoxib): This study is identical to the indomethacin functional activation study, except either rofecoxib or celecoxib is given instead of indomethacin. Because they are given orally instead of through a vein, the second scan is delayed 2 hours to allow time for the drug to be absorbed.

Study Overview

Status

Completed

Conditions

Detailed Description

Advances in MR perfusion imaging have provided clinical researchers with the opportunity to quantify regional increases in cerebral blood flow. The purpose of this study is to investigate in humans the role of prostaglandins in the regulation of cerebral blood flow during hypercapnia and functional activation. For this investigation the increase in cerebral blood flow associated with either hypercapnia or functional activation will be measured before and after the administration of pharmacological agents that inhibit the production of prostaglandins. In the hypercapnia study cerebral blood flow will be increased by inhalation of an air mixture containing 6% CO2. For the functional activation study cerebral blood flow will be increased by a sensory motor task.

Study Type

Observational

Enrollment

125

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Maryland
      • Bethesda, Maryland, United States, 20892
        • Warren G. Magnuson Clinical Center (CC)

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

INCLUSION CRITERIA:

Any healthy normal volunteer above the age of 18 who is capable of giving informed consent.

EXCLUSION CRITERIA:

Subjects will be excluded for the following reasons.

They have contraindications to MR scanning, such as the following: aneurysm clip, implanted neural stimulator, implanted cardiac pacemaker or autodefibrillator, cochlear implant, ocular foreign body (e.g., metal shavings), or insulin pump.

They have panic disorder or migraine (because of possible complications with CO2 inhalation).

They have cirrhosis, any renal dysfunction, or a chronic respiratory illness (such as asthma).

They have allergies to sulfonamide drugs or cyclo-oxygenase inhibitors (NSAIDS).

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

National Institutes of Health Clinical Center (CC)

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

September 1, 2000

Study Completion

December 1, 2003

Study Registration Dates

First Submitted

September 30, 2000

First Submitted That Met QC Criteria

September 30, 2000

First Posted (Estimate)

October 2, 2000

Study Record Updates

Last Update Posted (Estimate)

March 4, 2008

Last Update Submitted That Met QC Criteria

March 3, 2008

Last Verified

December 1, 2003

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 000226
  • 00-CC-0226

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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