Role of Adenosine in the Control of Choroidal Blood Flow During Changes in Ocular Perfusion Pressure.

This study has been completed.
Sponsor:
Information provided by:
Medical University of Vienna
ClinicalTrials.gov Identifier:
NCT00712764
First received: July 8, 2008
Last updated: NA
Last verified: December 2006
History: No changes posted
  Purpose

Autoregulation is the ability of a vascular bed to maintain blood flow despite changes in perfusion pressure. For a long time it had been assumed that the choroid is a strictly passive vascular bed, which shows no autoregulation. However, recently several groups have identified some autoregulatory capacity of the human choroid. In the brain and the retina the mechanism behind autoregulation is most likely linked to changes in transmural pressure. In this model arterioles change their vascular tone depending on the pressure inside the vessel and outside the vessel. In the choroid, several observations argue against a direct involvement of arterioles. However, the mechanism behind choroidal autoregulation remains unclear. Adenosine, an endogenous purine metabolic end product with a potent vasodilatory effect on multiple vascular beds, leads to an increase in retinal and choroidal vessel diameter. The present study aims to investigate whether adenosine plays a role in choroidal autoregulation during a decrease in ocular perfusion pressure, which will be achieved by an increase in intraocular pressure.

Pressure/flow relationships will be investigated in the absence and presence of adenosine.


Condition Intervention
Ocular Physiology
Microcirculation
Drug: Adenosine
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: Role of Adenosine in the Control of Choroidal Blood Flow During Changes in Ocular Perfusion Pressure.

Resource links provided by NLM:


Further study details as provided by Medical University of Vienna:

Primary Outcome Measures:
  • choroidal pressure-flow relationship [ Time Frame: 2 hours at 2 study days ] [ Designated as safety issue: No ]

Enrollment: 20
Study Start Date: January 2005
Study Completion Date: April 2005
Primary Completion Date: April 2005 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: 1 Drug: Adenosine
Placebo Comparator: 2 Drug: 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 (Must et al. 1991)
  • 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
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Please refer to this study by its ClinicalTrials.gov identifier: NCT00712764

Locations
Austria
Department of Clinical Pharmacology, Medical University of Vienna
Vienna, Austria, 1090
Sponsors and Collaborators
Medical University of Vienna
Investigators
Principal Investigator: Michael Wolzt, MD Department of Clinical Pharmacology, Medical University of Vienna
  More Information

No publications provided by Medical University of Vienna

Additional publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: Michael Wolzt, MD, Department of Clinical Pharmacology, Medical University of Vienna
ClinicalTrials.gov Identifier: NCT00712764     History of Changes
Other Study ID Numbers: OPHT-011206
Study First Received: July 8, 2008
Last Updated: July 8, 2008
Health Authority: Austria: Federal Ministry for Health and Women

Keywords provided by Medical University of Vienna:
Adenosine
Choroidal blood flow
Suction cup

Additional relevant MeSH terms:
Adenosine
Analgesics
Sensory System Agents
Peripheral Nervous System Agents
Physiological Effects of Drugs
Pharmacologic Actions
Central Nervous System Agents
Therapeutic Uses
Anti-Arrhythmia Agents
Cardiovascular Agents
Vasodilator Agents

ClinicalTrials.gov processed this record on September 16, 2014