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

NCT00280501 | Completed DMC

• 1 other identifier: OPHT-160905
• Study Type: interventional
• Target: 21
• 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 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

Keywords

Sulpiride; Quetiapine; Light/dark transition; Choroidal blood flow

Outcome Measures

Primary Outcomes (2)

• choroidal blood flow

  in total 3x 3 hours

• fundus pulsation amplitude

  in total 3 x 3 hours

Study Arms (3)

1

ACTIVE COMPARATOR

Quetiapine

Drug: Quetiapine (drug); Drug: Sulpiride (drug); Drug: Placebo

2

ACTIVE COMPARATOR

Sulpiride

Drug: Quetiapine (drug); Drug: Sulpiride (drug); Drug: Placebo

3

PLACEBO COMPARATOR

Placebo

Drug: Quetiapine (drug); Drug: Sulpiride (drug); Drug: Placebo

Interventions

Quetiapine (drug) DRUG

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

1; 2; 3

Sulpiride (drug) DRUG

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

1; 2; 3

Placebo DRUG

Placebo

1; 2; 3

Eligibility Criteria

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

You may qualify if:

• 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.

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

Vienna, 1090, Austria

Location

MeSH Terms

Interventions

Quetiapine Fumarate; Pharmaceutical Preparations; Sulpiride

Intervention Hierarchy (Ancestors)

Dibenzothiazepines; Thiazepines; Thiepins; Sulfur Compounds; Organic Chemicals; Heterocyclic Compounds, 3-Ring; Heterocyclic Compounds, Fused-Ring; Heterocyclic Compounds; Benzamides; Amides; Benzoates; Acids, Carbocyclic; Carboxylic Acids; Benzene Derivatives; Hydrocarbons, Aromatic; Hydrocarbons, Cyclic; Hydrocarbons

Study Officials

• Gabriele Fuchsjaeger-Mayrl, MD

  Department of Clinical Pharmacology

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER

Study Record Dates

• First Submitted: January 19, 2006
• First Posted: January 23, 2006
• Study Start: August 1, 2005
• Primary Completion: August 1, 2006
• Study Completion: August 1, 2006
• Last Updated: July 9, 2008

Record last verified: 2008-07

Locations

AU (1)