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

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ClinicalTrials.gov Identifier: NCT00280501
Recruitment Status : Completed
First Posted : January 23, 2006
Last Update Posted : July 9, 2008
Sponsor:
Information provided by:
Medical University of Vienna

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.


Condition or disease Intervention/treatment Phase
Regional Blood Flow Ocular Physiology Drug: Quetiapine (drug) Drug: Sulpiride (drug) Drug: Placebo Not Applicable

Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 21 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double (Participant, Investigator)
Primary Purpose: Treatment
Official Title: Dopaminergic Modulation of Choroidal Blood Flow Changes During Dark/Light Transitions
Study Start Date : August 2005
Actual Primary Completion Date : August 2006
Actual Study Completion Date : August 2006

Resource links provided by the National Library of Medicine

Drug Information available for: Quetiapine
U.S. FDA Resources

Arm Intervention/treatment
Active Comparator: 1
Quetiapine
Drug: Quetiapine (drug)
Quetiapine (Seroquel 100mg-film-coated tablet, AstraZeneca Vienna, Austria) Dose: 100 mg tablet oral single dose
Drug: Sulpiride (drug)
Sulpiride (Dogmatil 200mg-tablet, Synthélabo Groupe, Le Plessis Robinson, France) Dose: one half of 200 mg tablet oral single dose
Drug: Placebo
Placebo
Active Comparator: 2
Sulpiride
Drug: Quetiapine (drug)
Quetiapine (Seroquel 100mg-film-coated tablet, AstraZeneca Vienna, Austria) Dose: 100 mg tablet oral single dose
Drug: Sulpiride (drug)
Sulpiride (Dogmatil 200mg-tablet, Synthélabo Groupe, Le Plessis Robinson, France) Dose: one half of 200 mg tablet oral single dose
Drug: Placebo
Placebo
Placebo Comparator: 3
Placebo
Drug: Quetiapine (drug)
Quetiapine (Seroquel 100mg-film-coated tablet, AstraZeneca Vienna, Austria) Dose: 100 mg tablet oral single dose
Drug: Sulpiride (drug)
Sulpiride (Dogmatil 200mg-tablet, Synthélabo Groupe, Le Plessis Robinson, France) Dose: one half of 200 mg tablet oral single dose
Drug: Placebo
Placebo



Primary Outcome Measures :
  1. choroidal blood flow [ Time Frame: in total 3x 3 hours ]
  2. fundus pulsation amplitude [ Time Frame: in total 3 x 3 hours ]


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Ages Eligible for Study:   18 Years to 35 Years   (Adult)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   Yes
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

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00280501


Locations
Austria
Department of Clinical Pharmacology
Vienna, Austria, 1090
Sponsors and Collaborators
Medical University of Vienna
Investigators
Principal Investigator: Gabriele Fuchsjaeger-Mayrl, MD Department of Clinical Pharmacology

Responsible Party: Gabriele Fuchsjaeger-Mayrl, MD, Department of Clinical Pharmacology, Medical University of Vienna
ClinicalTrials.gov Identifier: NCT00280501     History of Changes
Other Study ID Numbers: OPHT-160905
First Posted: January 23, 2006    Key Record Dates
Last Update Posted: July 9, 2008
Last Verified: July 2008

Keywords provided by Medical University of Vienna:
Sulpiride
Quetiapine
Light/dark transition
Choroidal blood flow

Additional relevant MeSH terms:
Quetiapine Fumarate
Sulpiride
Dopamine
Dopamine Agents
Dopamine Agonists
Antipsychotic Agents
Tranquilizing Agents
Central Nervous System Depressants
Physiological Effects of Drugs
Psychotropic Drugs
Cardiotonic Agents
Sympathomimetics
Autonomic Agents
Peripheral Nervous System Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action
Protective Agents
Dopamine Antagonists
Antidepressive Agents, Second-Generation
Antidepressive Agents