THE EFFECT OF ARTERIAL-PRESSURE ON THE OCULAR PRESSURE-VOLUME RELATIONSHIP IN THE RABBIT
THE EFFECT OF ARTERIAL-PRESSURE ON THE OCULAR PRESSURE-VOLUME RELATIONSHIP IN THE RABBIT
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DOI：
10.1016/s0014-4835(05)80109-5
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发表时间：
1995-03-01
影响因子：
3.4
通讯作者：
KIEL, JW
中科院分区：
文献类型：
--
作者：
KIEL, JW
本研究的目的是量化平均动脉压（MAP）对眼压-容积关系的影响。实验在戊巴比妥钠麻醉的家兔上进行，在胸主动脉和下腔静脉上安装封堵器以控制MAP，通过耳中央动脉插管测量MAP。为了改变眼球体积并测量眼内压（IOP），将两个23号针头通过睫状体平坦部插入玻璃体中：一个针头连接到盐水填充的注射器，另一个针头连接到压力传感器。在一组动物（n = 5）中，在MAP为100、80、60、40和20 mmHg时测定压力-容积曲线，并在死后每隔1-1.5秒累积注射盐水（2 μ l）。在第二组（n = 7）中，在MAP为80、60和40 mmHg时获得压力-容积曲线，并在死后以0.5 μ l/s（-1）输注盐水直至IOP达到100 mmHg。在第三组（n = 11）中重复输注方案，其中通过激光多普勒流量计测量脉络膜流量和运动血细胞浓度（CMBC），分别作为脉络膜血流量和血容量的指标。MAP对眼压-容积关系有三个主要影响：（1）基线IOP随MAP呈指数变化，（2）压力-容积曲线初始部分的陡度是MAP依赖性的，（3）当MAP大于或等于40 mmHg时，IOP接近主MAP时，曲线显示“平台”。当IOP超过当时的MAP时，活体眼的所有曲线都变得与死后曲线不可区分。通量和CMBC测量表明，曲线的初始部分的MAP依赖性是由于脉络膜自动调节的失败和较低MAP下脉络膜血容量的增加减少，并且曲线的平台部分是由于血液从眼睛排出。结论：MAP对眼压-容积关系有显著影响。
The purpose of this study was to quantify the effect of mean arterial pressure (MAP) on the ocular pressure-volume relationship. The experiments were performed in pentobarbital anesthetized rabbits instrumented with occluders on the thoracic aorta and inferior vena cava to control MAP which was measured via a cannula in the central ear artery. To vary the ocular volume and measure the intraocular pressure (IOP), two 23 gauge needles were inserted through the pars plana into the vitreous: one needle was connected to a saline-filled syringe and the other needle was connected to a pressure transducer. In one group of animals (n = 5), pressure-volume curves were determined at MAPs of 100, 80, 60, 40 and 20 mmHg and post mortem by cumulative saline injections (2 mu l) every 1-1.5 sec. In a second group (n = 7), pressure-volume curves were obtained at MAPs of 80, 60 and 40 mmHg and post mortem by saline infusion at 0.5 mu l sec(-1) until the IOP reached 100 mmHg. The infusion protocol was repeated in a third group (n = 11) where the choroidal flux and the concentration of moving blood cells (CMBC) were measured by a laser Doppler flowmeter as indices of choroidal blood now and the blood volume, respectively. MAP had three primary effects on the ocular pressure-volume relationship: (1) the baseline IOP varied exponentially with MAP, (2) the steepness of the initial portion of the pressure-volume curves was MAP-dependent and (3) the curves exhibited a 'plateau' as the IOP approached the prevailing MAP at MAPs greater than or equal to 40 mmHg. All of the curves in the living eye intersected and became indistinguishable from the post mortem curve when the IOP exceeded the prevailing MAP. The flux and CMBC measurements indicated that the MAP-dependence of the initial portion of the curves was due to failure of choroidal autoregulation and diminished increases in choroidal blood volume at the lower MAPs, and that the plateau portion of the curves was due to expulsion of blood from the eye. It is concluded that MAP has a significant effect on the ocular pressure-volume relationship.