Brain Receptors in Sympathetic Nervous System Regulation

• Status: Completed
• Trial end date: 2004-12-01
• Target enrollment: 0
• Participant gender: All

Summary

The purpose of this study is to investigate the role of brain receptors called alpha2-adrenoreceptors in regulating the sympathetic nervous system, which maintains the supply of blood and fuel to the body's organs in times of stress, fear, anger, or exercise.

Alpha(2)-adrenergic receptors (alpha(2)-AR) play a role in a variety of physiological functions. There are three subtypes of alpha(2)-ARs, and their differences are unknown. This study will examine the functional roles of these three subtypes by comparing the behavioral, biochemical, psychophysiological, and autonomic function effects of the alpha(2)-AR drugs clonidine and yohimbine.

Participants in this study will undergo a physical examination, electrocardiogram (ECG), and blood, urine, and saliva tests. Women will have hormone tests to determine the time of their last period and the time of their next ovulation. Participants will undergo neuropsychological testing and other procedures.

• Accepts Healthy Volunteers?: Accepts Healthy Volunteers

Details

• Lead Sponsor: National Institute of Mental Health (NIMH)
• Treatments: Yohimbine

Criteria

INCLUSION CRITERIA

Healthy subjects with a negative first-degree family history of psychiatric disorders as determined by the Family Interview of Genetic Studies are eligible.

Subjects must be willing to participate in a challenge study.

Subjects must be in good physical health.

Subjects must have the absence of any Axis I and Axis II DSM-IV diagnosis.

Subjects will be excluded if they have evidence for an axis I psychiatric disorder or the presence of an axis II personality disorder.

Smokers are ineligible to participate.

Subjects with recent life stressors (3 months) or chronic life stressors (1 year) will be ineligible.

Subjects must be between the ages of 18 and 50.

Subjects must meet criteria for one of 6 genotypically defined subgroups.

Subjects must not have taken antidepressant or other medications likely to alter monoamine neurochemistry or cerebrovascular and cardiovascular function for at least 6 months prior to the challenge studies.

EXCLUSION CRITERIA

Subjects will be excluded if they have medical or neurological illnesses likely to affect physiology or anatomy, i.e. hypertension, cardiovascular disorders.

Subjects must not have a history of drug (including BZDs) or alcohol abuse within 1 year or a lifetime history of alcohol or drug dependence.

Subjects with current or previous regular use (greater than 4 weeks) of BZDs and excessive use of alcohol (greater than 8 ounces/week for men and greater than 6 ounces/week for women) in the past or present are ineligible to participate.

Women who are currently pregnant or breastfeeding are not eligible.

Subjects who cannot hear a 40 dB(HL) pure tone in the 1000- to 4000 Hz span (Welsh Allen audioscope) will be excluded from studies.