Clinical trial NCT00280501: Dopaminergic Modulation of Choroidal Blood Flow Changes During Dark/Light Transitions
Official title: Dopaminergic Modulation of Choroidal Blood Flow Changes During Dark/Light Transitions
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Regional Blood Flow
Ocular Physiology
Keywords: Sulpiride
Quetiapine
Light/dark transition
Choroidal blood flow
Lead sponsor: Medical University of Vienna
Sponsor class: OTHER
First posted: 2006-01-23
Enrollment: 21
Sex: MALE
Minimum age (years): 18
Maximum age (years): 35
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: TREATMENT

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.


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

Primary outcomes:
measure: choroidal blood flow
timeFrame: in total 3x 3 hours
measure: fundus pulsation amplitude
timeFrame: in total 3 x 3 hours
Secondary outcomes:
Other outcomes:
Locations:
city: Vienna
country: Austria
facility: Department of Clinical Pharmacology
Study officials:
affiliation: Department of Clinical Pharmacology
name: Gabriele Fuchsjaeger-Mayrl, MD
role: PRINCIPAL_INVESTIGATOR
References: