Dopaminergic Modulation of Choroidal Blood Flow Changes During Dark/Light Transitions

NCT ID: NCT00280501

Last Updated: 2008-07-09

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 21 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2005-08-31
• Study Completion Date: 2006-08-31

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 reduction in choroidal blood flow due to an unknown mechanism. We have shown that during unilateral dark/light transitions both eyes react with choroidal vasoconstriction strongly indicating a neural mechanism responsible for the blood flow changes.

Dopamine has been discussed as a chemical messenger for light adaptation. However, dopaminergic effects in the eye are not restricted to synaptic sites of release, but dopamine also diffuses to the outer retinal layers and pigment epithelium. Accordingly, dopaminergic effects also include a modulatory role on retinal vessel diameter and animal studies provide evidence for vasodilatory effects in the choroid. There is evidence that during darkness retinal and choroidal dopamine levels decrease. Accordingly, dopamine could provide a modulatory input to the light/dark transition induced changes of choroidal circulation. The aim of the present study is to test this hypothesis.

Conditions

Regional Blood Flow; Ocular Physiology

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: TREATMENT
• Blinding Strategy: DOUBLE

Study Groups

1

Quetiapine

Group Type: ACTIVE_COMPARATOR

Quetiapine (drug)

Intervention Type: DRUG

Quetiapine (Seroquel 100mg-film-coated tablet, AstraZeneca Vienna, Austria) Dose: 100 mg tablet oral single dose

Sulpiride (drug)

Intervention Type: DRUG

Sulpiride (Dogmatil 200mg-tablet, Synthélabo Groupe, Le Plessis Robinson, France) Dose: one half of 200 mg tablet oral single dose

Placebo

Intervention Type: DRUG

Placebo

2

Sulpiride

Group Type: ACTIVE_COMPARATOR

Quetiapine (drug)

Intervention Type: DRUG

Quetiapine (Seroquel 100mg-film-coated tablet, AstraZeneca Vienna, Austria) Dose: 100 mg tablet oral single dose

Sulpiride (drug)

Intervention Type: DRUG

Sulpiride (Dogmatil 200mg-tablet, Synthélabo Groupe, Le Plessis Robinson, France) Dose: one half of 200 mg tablet oral single dose

Placebo

Intervention Type: DRUG

Placebo

3

Placebo

Group Type: PLACEBO_COMPARATOR

Quetiapine (drug)

Intervention Type: DRUG

Quetiapine (Seroquel 100mg-film-coated tablet, AstraZeneca Vienna, Austria) Dose: 100 mg tablet oral single dose

Sulpiride (drug)

Intervention Type: DRUG

Sulpiride (Dogmatil 200mg-tablet, Synthélabo Groupe, Le Plessis Robinson, France) Dose: one half of 200 mg tablet oral single dose

Placebo

Intervention Type: DRUG

Placebo

Interventions

Quetiapine (drug)

Quetiapine (Seroquel 100mg-film-coated tablet, AstraZeneca Vienna, Austria) Dose: 100 mg tablet oral single dose

Intervention Type: DRUG

Sulpiride (drug)

Sulpiride (Dogmatil 200mg-tablet, Synthélabo Groupe, Le Plessis Robinson, France) Dose: one half of 200 mg tablet oral single dose

Intervention Type: DRUG

Placebo

Placebo

Intervention Type: DRUG

Eligibility Criteria

Inclusion Criteria

• Men aged between 18 and 35 years, nonsmokers
• Body mass index between 15th and 85th percentile
• 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, ametropia < 3 Dpt.

Exclusion Criteria

• 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

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 35 Years
• Eligible Sex: MALE
• Accepts Healthy Volunteers: Yes

Sponsors

Medical University of Vienna

OTHER

Sponsor Role: lead

Responsible Party

Department of Clinical Pharmacology, Medical University of Vienna

Principal Investigators

Gabriele Fuchsjaeger-Mayrl, MD

Role: PRINCIPAL_INVESTIGATOR

Department of Clinical Pharmacology

Locations

Department of Clinical Pharmacology

Vienna, , Austria

Countries

Austria

Other Identifiers

OPHT-160905

Identifier Type: -

Identifier Source: org_study_id