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Role of Adenosine in the Control of Choroidal Blood Flow During Changes in Ocular Perfusion Pressure.
This study has been completed.
Study NCT00712764   Information provided by Medical University of Vienna
First Received: July 8, 2008   No Changes Posted

July 8, 2008
July 8, 2008
January 2005
April 2005   (final data collection date for primary outcome measure)
choroidal pressure-flow relationship [ Time Frame: 2 hours at 2 study days ] [ Designated as safety issue: No ]
Same as current
No Changes Posted
 
 
 
Role of Adenosine in the Control of Choroidal Blood Flow During Changes in Ocular Perfusion Pressure.
Role of Adenosine in the Control of Choroidal Blood Flow During Changes in Ocular Perfusion Pressure.

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.

 
 
Interventional
Treatment, Randomized, Double Blind (Subject, Investigator), Placebo Control, Crossover Assignment, Safety/Efficacy Study
  • Ocular Physiology
  • Microcirculation
  • Drug: Adenosine
  • Drug: Placebo
 
 

*   Includes publications given by the data provider as well as publications identified by National Clinical Trials Identifier (NCT ID) in Medline.
 
Completed
20
April 2005
April 2005   (final data collection date for primary outcome measure)

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
Male
18 Years to 35 Years
Yes
Contact information is only displayed when the study is recruiting subjects
Austria
 
NCT00712764
Michael Wolzt, MD, Department of Clinical Pharmacology, Medical University of Vienna
OPHT-011206
Medical University of Vienna
 
Principal Investigator: Michael Wolzt, MD Department of Clinical Pharmacology, Medical University of Vienna
Medical University of Vienna
December 2006

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP