Robinson J C, Kaufman P L
Department of Ophthalmology, University of Wisconsin School of Medicine, Madison 53792.
Am J Ophthalmol. 1990 Feb 15;109(2):189-94. doi: 10.1016/s0002-9394(14)75985-9.
Total outflow facility was determined in cynomolgus monkeys by two-level constant pressure perfusion. Topical epinephrine increased facility by 30% to 35% three to four hours after dosing, whether given as a single 600-micrograms dose or as twice daily 600-micrograms doses for three days. A single 5.5-micrograms intracameral dose of epinephrine or norepinephrine increased facility by 65% to 70% three to four hours after dosing. A single 180-micrograms topical dose of timolol or betaxolol had no effect on facility three to four hours later. Timolol pretreatment prevented the facility-increasing effect of both topical epinephrine and intracameral norepinephrine, but betaxolol pretreatment prevented neither. These findings indicate that no cumulative facility-increasing effect of epinephrine, beyond the acute (three hour) facility-increasing effect, develops within three days; there may be a facility-decreasing effect of large topical epinephrine doses on the vascular structures external to the trabecular meshwork; there is no, or only subthreshold, facility-affecting ambient beta-adrenergic tone in the meshwork; and the facility-increasing effect of both epinephrine and norepinephrine is mediated by beta 2-adrenergic receptors in the trabecular endothelium.
通过两级恒压灌注法测定食蟹猴的总房水流出率。局部应用肾上腺素后，无论单次给予600微克剂量还是连续三天每日两次给予600微克剂量，给药后三到四小时房水流出率增加30%至35%。前房内单次给予5.5微克肾上腺素或去甲肾上腺素后，给药后三到四小时房水流出率增加65%至70%。局部单次给予180微克噻吗洛尔或倍他洛尔，三到四小时后对房水流出率无影响。噻吗洛尔预处理可阻止局部应用肾上腺素和前房内应用去甲肾上腺素后房水流出率增加的效应，但倍他洛尔预处理则不能。这些发现表明，在三天内，肾上腺素除了急性（三小时）增加房水流出率的效应外，不会产生累积效应；大剂量局部应用肾上腺素可能对小梁网外部的血管结构有降低房水流出率的作用；小梁网中不存在或仅存在阈下的、影响房水流出率的环境β-肾上腺素能张力；肾上腺素和去甲肾上腺素增加房水流出率的效应是由小梁内皮细胞中的β2-肾上腺素能受体介导的。
