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

This study has been completed.
Sponsor:
Information provided by:
Medical University of Vienna
ClinicalTrials.gov Identifier:
NCT00280501
First received: January 19, 2006
Last updated: July 8, 2008
Last verified: July 2008
  Purpose

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 Intervention
Regional Blood Flow
Ocular Physiology
Drug: Quetiapine (drug)
Drug: Sulpiride (drug)
Drug: Placebo

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Crossover Assignment
Masking: Double Blind (Subject, Investigator)
Primary Purpose: Treatment
Official Title: Dopaminergic Modulation of Choroidal Blood Flow Changes During Dark/Light Transitions

Resource links provided by NLM:


Further study details as provided by Medical University of Vienna:

Primary Outcome Measures:
  • choroidal blood flow [ Time Frame: in total 3x 3 hours ] [ Designated as safety issue: No ]
  • fundus pulsation amplitude [ Time Frame: in total 3 x 3 hours ] [ Designated as safety issue: No ]

Enrollment: 21
Study Start Date: August 2005
Study Completion Date: August 2006
Primary Completion Date: August 2006 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
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

  Eligibility

Ages Eligible for Study:   18 Years to 35 Years
Genders 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
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: 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
  More Information

No publications provided

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
Study First Received: January 19, 2006
Last Updated: July 8, 2008
Health Authority: Austria: Federal Ministry for Health and Women

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

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

ClinicalTrials.gov processed this record on July 28, 2014