NCT00431392

Mechanisms of Choroidal Blood Flow Changes During Dark/Light Transitions

• Status: Completed
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 42 (planned)
• Sponsor: Medical University of Vienna · Academic / Other
• Sex: Male
• Age: 19 Years – 35 Years
• Healthy volunteers: Accepted

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 short lasting reduction in choroidal blood flow. We have shown that during unilateral dark/light transition both eyes react with choroidal vasoconstriction strongly indicating a neural mechanism. The present studies investigate this possibility by using pharmacological interventions. The pharmacological agents tested include a nitric oxide synthase inhibitor, an alpha-receptor agonist (as a control substance for the blood pressure increasing nitric oxide synthase inhibitor), a muscarinic receptor blocker, and a non-specific beta-blocker. These drugs were chosen on the basis of previous animal experiments, as the systems, which are specifically influenced by these substances, are likely involved in neural control of choroidal blood flow.

Conditions

• Regional Blood Flow
• Ocular Physiology

Interventions

Type	Name	Description
DRUG	Phenylephrine
DRUG	NG-Monomethyl-L-Arginine
DRUG	Propanolol
DRUG	Atropine

Timeline

• Start date: 2001-09-01
• First posted: 2007-02-05
• Last updated: 2007-02-05

Locations

1 site across 1 country: Austria