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Role of Endothelin-1 in Optic Nerve Head Blood Flow Regulation During Isometric Exercise in Healthy Humans

NCT00915070 · Status: COMPLETED · Phase: NA · Type: INTERVENTIONAL · Enrollment: 16

Last updated 2012-08-10

No results posted yet for this study

Summary

Autoregulation is defined as the ability of a vascular bed to adapt its vascular resistance to changes in perfusion pressure. In the eye, several studies have reported that retinal blood flow is autoregulated over a wide range of ocular perfusion pressures. The investigators could recently show that Endothelin-1 is a key metabolite in the regulation of vascular tone in the eye and plays an important role in the blood flow autoregulation of the choroidal circulation. However, no data is yet available for the optic nerve head. Thus, the present study is designed to test the hypothesis that Endothelin-1 plays also a role in optic nerve head blood flow autoregulation.

Therefore, subjects will perform squatting to increase systemic perfusion pressure during administration of either an endothelin A-receptor blocker (BQ-123) or placebo. Optic nerve head blood flow will be continuously measured during the procedure to investigate optic nerve head autoregulation.

Conditions

  • Healthy

Interventions

DRUG

BQ-123

60 mcg/min, infusion period: 60 min

DRUG

Physiological saline solution

infusion period 60 minutes

DEVICE

Laser Doppler Flowmetry

blood flow measurements at the temporal neuroretinal rim to assess optic nerve head blood flow

DEVICE

Goldmann Applanation Tonometer

intraocular pressure measurements

OTHER

squatting

subjects will perform squatting for 6 minutes while blood flow measurements

Sponsors & Collaborators

  • Medical University of Vienna

    lead OTHER

Principal Investigators

  • Gabriele Fuchsjaeger-Mayrl, MD, Univ.Doz · Department of Clinical Pharmacology, Medical University of Vienna

Study Design

Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
TRIPLE
Model
CROSSOVER

Eligibility

Min Age
18 Years
Max Age
35 Years
Sex
ALL
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2010-10-31
Primary Completion
2011-05-31
Completion
2011-12-31

Countries

  • Austria

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT00915070 on ClinicalTrials.gov