Belmonte C, Bartels S P, Liu J H, Neufeld A H
Ophthalmic Pharmacology Unit, Eye Research Institute of Retina Foundation, Boston, Massachusetts 02114.
Invest Ophthalmol Vis Sci. 1987 Oct;28(10):1649-54.
Ocular sympathetic nerves were stimulated chronically in awake rabbits using electrodes unilaterally implanted on the cervical sympathetic trunk. IOP was measured by pneumatonometry and aqueous inflow was measured by fluorophotometry. In each animal, continuous trains of 1 msec pulses were delivered by means of a portable electrical stimulator. Experiments were spaced by 1 week recovery periods. Stimulation was varied over a range of amplitudes (5-15 V) and frequencies (3-12 Hz). Continuous sympathetic stimulation produced an immediate sharp decrease in IOP followed by a gradual rise to pre-stimulation values which were attained 60-90 min after onset. A rebound increase in IOP occurred when stimulation was terminated. The magnitude of the initial IOP drop, the delay in the return to pre-stimulation IOP, and the rebound rise in IOP subsequent to termination of electrical stimulation were proportional to the stimulation frequency. Maximal effects were observed at 12 Hz, and stimulation with 8-10 Hz for 180 min caused a sustained reduction in anterior chamber aqueous humor flow. Topical 2% phentolamine 1 hr before stimulation markedly reduced IOP and abolished the acute IOP changes observed in untreated stimulated animals. Topical 1% timolol did not affect either the initial IOP drop or the rebound; however, the IOP recovered during stimulation to values greater than pre-stimulation IOP. We conclude that in rabbits the beta-adrenergic effect of prolonged sympathetic nerve stimulation is to decrease aqueous flow. Chronic electrical stimulation in awake animals provides an experimental model for studying the role of the ocular sympathetic nerves.
在清醒兔中，使用单侧植入颈交感干的电极对眼交感神经进行长期刺激。通过眼压计测量眼压，通过荧光光度法测量房水流入量。在每只动物中，借助便携式电刺激器施加持续1毫秒的脉冲序列。实验之间间隔1周的恢复期。刺激的幅度（5 - 15伏）和频率（3 - 12赫兹）范围有所变化。持续的交感神经刺激导致眼压立即急剧下降，随后逐渐上升至刺激前的值，该值在刺激开始后60 - 90分钟达到。当刺激终止时，眼压出现反弹性升高。眼压初始下降的幅度、恢复到刺激前眼压的延迟以及电刺激终止后眼压的反弹性升高与刺激频率成正比。在12赫兹时观察到最大效应，以8 - 10赫兹刺激180分钟导致前房房水流量持续减少。刺激前1小时局部应用2%酚妥拉明显著降低眼压，并消除了未治疗的受刺激动物中观察到的急性眼压变化。局部应用1%噻吗洛尔既不影响眼压的初始下降也不影响反弹性升高；然而，眼压在刺激期间恢复到高于刺激前眼压的值。我们得出结论，在兔中，延长的交感神经刺激的β - 肾上腺素能效应是减少房水流量。清醒动物的慢性电刺激为研究眼交感神经的作用提供了一个实验模型。
