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

Regional Blood Flow Clinical Trial

Official title:

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

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT00280501
• Other study ID #: OPHT-160905
• Status: Completed
• Phase: N/A
• First received: January 19, 2006
• Last updated: July 8, 2008
• Start date: August 2005
• Est. completion date: August 2006

Study information

• Verified date: July 2008
• Source: Medical University of Vienna
• Contact: n/a
• Is FDA regulated: No
• Health authority: Austria: Federal Ministry for Health and Women
• Study type: Interventional

Clinical Trial 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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 21
• Est. completion date: August 2006
• Est. primary completion date: August 2006
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Male
• Age group: 18 Years to 35 Years

Eligibility

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

Study Design

Allocation: Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Crossover Assignment, Masking: Double Blind (Subject, Investigator), Primary Purpose: Treatment

Related Conditions & MeSH terms

• Ocular Physiology
• Regional Blood Flow

Intervention

Drug:
• Quetiapine (drug)
Quetiapine (Seroquel 100mg-film-coated tablet, AstraZeneca Vienna, Austria) Dose: 100 mg tablet oral single dose
• Sulpiride (drug)
Sulpiride (Dogmatil 200mg-tablet, Synthélabo Groupe, Le Plessis Robinson, France) Dose: one half of 200 mg tablet oral single dose
• Placebo
Placebo

Locations

Country	Name	City	State
Austria	Department of Clinical Pharmacology	Vienna

Sponsors (1)

Lead Sponsor	Collaborator
Medical University of Vienna

Country where clinical trial is conducted

Austria, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	choroidal blood flow		in total 3x 3 hours	No
Primary	fundus pulsation amplitude		in total 3 x 3 hours	No