Recruiting
Phase 2

Observational Study

Sponsor:

University of Wisconsin, Madison

Code:

NCT06629077

Conditions

Magnetic Resonance Imaging

Cerebrovascular Circulation

Eligibility Criteria

Sex: All

Age: 55 - 69

Healthy Volunteers: Accepted

Interventions

MRI

Prazosin

Placebo

Study Details

Brief summary:

Brain blood flow will be measured during a simulated postural change test and while breathing increased levels of carbon dioxide using magnetic resonance imaging.

Conditions

Magnetic Resonance Imaging

Cerebrovascular Circulation

Study ID

NCT06629077

Start date

Feb 26, 2026

Status verified date

Feb, 2026

Completion date

Jan, 2027

Anticipated

Primary completion date

Jan, 2027

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 55 - 69

Healthy Volunteers: Accepted

Inclusion Criteria:

  • Between the ages of 55-69 years
  • Have a BMI less than or equal to 34.5 kg/m2
  • Nonsmoker
  • are less than 72 in (182.88 cm) height
  • Females must be postmenopausal

Exclusion Criteria:

  • Diagnosis of Mild Cognitive Impairment (MCI) or Alzheimer's disease (AD)
  • History or evidence of hepatic disease, hematological disease, or peripheral vascular disease; severe kidney injury requiring hemodialysis
  • History of cardiovascular disease including: severe congestive heart failure, coronary artery disease, ischemic heart disease (stents, coronary artery bypass grafts) and tachycardia
  • Uncontrolled hypertension
  • History of clinically significant ischemic or hemorrhagic stroke, or significant cerebrovascular disease
  • Severe untreated obstructive sleep apnea
  • History of diabetes with HbA1c greater than 9.5%
  • Major neurologic disorders other than dementia (e.g., MS, ALS, brain surgery, etc.)
  • Current or recent (\<1 year) major psychiatric condition (Axis I) or addictive disorders
  • Significant surgical history
  • Other significant medical conditions at investigators' discretion
  • Contraindications to MRI
  • Prescribed medications that interfere with prazosin
  • Lactose allergy
  • lower body will not fit in lower body negative pressure (LBNP) chamber (regardless of overall height and BMI).

Study Design

Enrollment

36 participants

Anticipated

Intervention Model

Single group

Primary purpose

Basic Science

Interventions and Outcome Measures

Arms

experimental: Middle-Aged Adults

Middle-Aged Adults between 55-69 years of age.

Interventions

MRI

Participants will undergo an MRI scan while performing breathing and a simulated postural change task.

Prazosin

A dose of prazosin will be administered based on body weight.

Placebo

Oral placebo

Primary outcome measure

  • Change in blood flow [ Time Frame: Two study visits, up to 240 minutes ]
  • Change in blood velocity [ Time Frame: Two study visits, up to 240 minutes ]

Central Contacts and Locations

Central contacts

Anna Howery

608-262-9572ahowery@wisc.edu

Locations

University of Wisconsin

Recruiting

Madison, Wisconsin, United States, 53705

Contacts

Anna J Howery, MS

608-262-9572barneslab@education.wisc.edu

Principal Investigator:

Jill N Barnes, PhD

More Information

Sponsor

University of Wisconsin, Madison

Last update posted

Mar 2, 2026

Last verified

Feb, 2026

Keywords

  • Magnetic Resonance Imaging
  • Brain Blood Flow
  • Lower Body Negative Pressure
  • Carbon Dioxide

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-09. This information was provided to ClinicalTrials.gov by University of Wisconsin, Madison on 2026-03-02.