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Mechanisms of Choroidal Blood Flow Changes During Dark/Light Transitions

NCT00431392 · Status: COMPLETED · Phase: PHASE2 · Type: INTERVENTIONAL · Enrollment: 42

Last updated 2007-02-05

No results posted yet for this study

Summary

There is evidence from a variety of animal studies that choroidal blood flow is under neural control. By contrast, only little information is available from human studies. Recent results indicate that a light/dark transition is associated with a short lasting reduction in choroidal blood flow. We have shown that during unilateral dark/light transition both eyes react with choroidal vasoconstriction strongly indicating a neural mechanism.

The present studies investigate this possibility by using pharmacological interventions. The pharmacological agents tested include a nitric oxide synthase inhibitor, an alpha-receptor agonist (as a control substance for the blood pressure increasing nitric oxide synthase inhibitor), a muscarinic receptor blocker, and a non-specific beta-blocker. These drugs were chosen on the basis of previous animal experiments, as the systems, which are specifically influenced by these substances, are likely involved in neural control of choroidal blood flow.

Conditions

  • Regional Blood Flow
  • Ocular Physiology

Interventions

DRUG

Phenylephrine

DRUG

NG-Monomethyl-L-Arginine

DRUG

Propanolol

DRUG

Atropine

Sponsors & Collaborators

  • Medical University of Vienna

    lead OTHER

Principal Investigators

  • Michael Wolzt, MD · Department of Clinical Pharmacology, Medical University of Vienna

Study Design

Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Model
CROSSOVER

Eligibility

Min Age
19 Years
Max Age
35 Years
Sex
MALE
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2001-09-30

Countries

  • Austria

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT00431392 on ClinicalTrials.gov