Mechanisms of Choroidal Blood Flow Changes During Dark/Light Transitions

NCT00431392 | Completed Phase 2

• 1 other identifier: OPHT-180601
• Study Type: interventional
• Target: 42
• Locations: 1 country
• Sites: 1

Brief 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

Keywords

Choroidal blood flow; NO-synthase; light/dark transition

Outcome Measures

Primary Outcomes (2)

• choroidal blood flow

• fundus pulsation amplitude

Interventions

Phenylephrine DRUG

NG-Monomethyl-L-Arginine DRUG

Propanolol DRUG

Atropine DRUG

Eligibility Criteria

• Age: 19 Years - 35 Years
• Sex: male
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Men aged between 19 and 35 years, nonsmokers
• Body mass index between 15th and 85th percentile (Must et al. 1991)
• Normal findings in the medical history and physical examination unless the investigator considers an abnormality to be clinically irrelevant
• Normal laboratory values unless the investigator considers an abnormality to be clinically irrelevant
• Normal ophthalmic findings, ametropy \< 3 Dpt.

You may not qualify if:

• Regular use of medication, abuse of alcoholic beverages, participation in a clinical trial in the 3 weeks preceding the study
• Treatment in the previous 3 weeks with any drug
• Symptoms of a clinically relevant illness in the 3 weeks before the first study day
• History of hypersensitivity to the trial drug or to drugs with a similar chemical structure
• History or presence of gastrointestinal, liver or kidney disease, or other conditions known to interfere with, distribution, metabolism or excretion of study drugs
• Blood donation during the previous 3 weeks

Sponsors & Collaborators

• Medical University of Vienna: lead

Study Sites (1)

Department of Clinical Pharmacology, Medical University of Vienna

Vienna, 1090, Austria

Location

MeSH Terms

Interventions

Phenylephrine; omega-N-Methylarginine; Propranolol; Atropine

Intervention Hierarchy (Ancestors)

Ethanolamines; Amino Alcohols; Alcohols; Organic Chemicals; Amines; Arginine; Amino Acids, Basic; Amino Acids; Amino Acids, Peptides, and Proteins; Amino Acids, Diamino; Amino Acids, Essential; Phenoxypropanolamines; Propanolamines; Propanols; Naphthalenes; Polycyclic Aromatic Hydrocarbons; Hydrocarbons, Aromatic; Hydrocarbons, Cyclic; Hydrocarbons; Polycyclic Compounds; Atropine Derivatives; Tropanes; Azabicyclo Compounds; Aza Compounds; Belladonna Alkaloids; Solanaceous Alkaloids; Alkaloids; Heterocyclic Compounds; Bridged Bicyclo Compounds, Heterocyclic; Heterocyclic Compounds, Bridged-Ring

Study Officials

• Michael Wolzt, MD

  Department of Clinical Pharmacology, Medical University of Vienna

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER

Study Record Dates

• First Submitted: February 2, 2007
• First Posted: February 5, 2007
• Study Start: September 1, 2001
• Last Updated: February 5, 2007

Record last verified: 2007-01

Locations

AU (1)