Choroidal Blood Flow Regulation During Isometric Exercise: Effects of Ca2+-Channel Blockade
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 21
- 试验地点
- 1
- 主要终点
- Choroidal pressure-blood flow relationship
研究概览
简要总结
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. In a previous project we were able to identify that the nitric oxide (NO) - system as well as the endothelin system are involved in choroidal blood flow regulation during isometric exercise.
In the present study autoregulation of the choroid during isometric exercise will be investigated and the pressure/flow relationships will be observed in the absence or presence of a calcium antagonist - nifedipine.
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 (Participant, Investigator)
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 more than 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
研究组 & 干预措施
1
Nifedipine
干预措施: Nifedipine (drug) (Drug)
1
Nifedipine
干预措施: L-Arginin (drug) (Drug)
1
Nifedipine
干预措施: Placebo (Drug)
2
L-Arginin
干预措施: Nifedipine (drug) (Drug)
2
L-Arginin
干预措施: L-Arginin (drug) (Drug)
2
L-Arginin
干预措施: Placebo (Drug)
3
Placebo
干预措施: Nifedipine (drug) (Drug)
3
Placebo
干预措施: L-Arginin (drug) (Drug)
3
Placebo
干预措施: Placebo (Drug)
结局指标
主要结局
Choroidal pressure-blood flow relationship
时间窗: in total 3x 3 hours
次要结局
未报告次要终点