Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.
Invest Ophthalmol Vis Sci. 2011 Jul 29;52(8):6035-9. doi: 10.1167/iovs.11-7491.
The purpose of the present study was to investigate whether the nucleoside adenosine is involved in the regulatory processes of choroidal blood flow (ChBF) during an experimental decrease in ocular perfusion pressure (OPP).
In this randomized, double-masked, placebo-controlled, two-way crossover study, 14 subjects received either intravenous adenosine or placebo on two different study days. The suction cup method was used for a stepwise increase in intraocular pressure (IOP). Subfoveal ChBF was measured by laser Doppler flowmetry. Mean arterial pressure (MAP) and IOP were measured noninvasively. Ocular perfusion pressure was calculated as OPP = 2/3MAP - IOP.
Adenosine increased ChBF significantly versus placebo before application of the suction cup (P < 0.05). When the suction cup was applied, a significant decrease in OPP was observed. This effect was comparable on all study days. The decrease in OPP was paralleled by a significant decrease in ChBF (maximum between -43% and -52%) which was less pronounced than the decrease in OPP (maximum between -62% and -64%). Neither placebo nor adenosine influenced the ChBF increase during suction cup-induced changes in OPP.
The data of the present study confirm that the human choroid shows some regulatory capacity during a decrease in OPP. Adenosine influences basal vascular tone in the choroid but is not involved in the regulatory mechanisms during an increase in IOP. (ClinicalTrials.gov number, NCT00712764.).
本研究旨在探讨在实验性眼灌注压（OPP）降低期间，核苷腺苷是否参与脉络膜血流（ChBF）的调节过程。
在这项随机、双盲、安慰剂对照、两向交叉研究中，14 名受试者在两天的不同研究日分别接受静脉内腺苷或安慰剂治疗。使用吸盘法逐步增加眼内压（IOP）。通过激光多普勒血流仪测量中心凹下脉络膜血流。平均动脉压（MAP）和 IOP 均进行非侵入性测量。眼灌注压计算为 OPP=2/3MAP-IOP。
与安慰剂相比，腺苷在应用吸盘前可显著增加 ChBF（P<0.05）。当应用吸盘时，观察到 OPP 显著下降。这种效应在所有研究日都相当。OPP 的下降与 ChBF 的显著下降平行（最大下降幅度为-43%至-52%），小于 OPP 的下降幅度（最大下降幅度为-62%至-64%）。无论是安慰剂还是腺苷都没有影响在吸盘诱导的 OPP 变化期间 ChBF 的增加。
本研究的数据证实，人类脉络膜在 OPP 降低期间表现出一定的调节能力。腺苷影响脉络膜的基础血管张力，但在 IOP 增加期间不参与调节机制。（临床试验.gov 编号，NCT00712764.）。
