Mechanisms of Choroidal Blood Flow Changes During Dark/Light Transitions
试验速览
- 阶段
- 2 期
- 状态
- 已完成
- 入组人数
- 42
- 试验地点
- 2
- 主要终点
- choroidal blood flow
研究概览
简要总结
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.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Treatment
- 盲法
- Double
入排标准
- 年龄范围
- 19 Years 至 35 Years（Adult）
- 性别
- Male
- 接受健康志愿者
- 是
入选标准
- •Men aged between 19 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, ametropy < 3 Dpt.
排除标准
- •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
结局指标
主要结局
choroidal blood flow
fundus pulsation amplitude
次要结局
未报告次要终点