Frambach D A, Valentine J L, Weiter J J
Eye Research Institute of Retina Foundation, Boston, Massachusetts.
Invest Ophthalmol Vis Sci. 1989 Feb;30(2):343-4.
Rabbit retinal pigment epithelium (RPE) has an alpha-1 adrenoreceptor that substantially reduces RPE short circuit current (Isc) when stimulated. Since phenylephrine is a potent alpha adrenergic agonist frequently used to obtain pupil dilation, we examined the effect of topically applied phenylephrine for pupil dilation on RPE transport. Naive black dutch-belted rabbits received either one drop of 10% phenylephrine applied at t = 0 and t = 30 min or one drop of 1% cyclopentolate applied at t = 30 min. At t = 50 min, RPE-choroid-sclera explants from these animals were sealed in an Ussing chamber. At t = 60-70 min, 1.4 X 10(-4) M epinephrine was introduced into both sides of the Ussing chamber. The change in Isc produced by epinephrine was measured. The Isc reduction in rabbits receiving phenylephrine was 26% (+/- 5% SD, n = 6). The Isc reduction in rabbits receiving cyclopentolate was 39% (+/- 6% SD, n = 5). These values are significantly different (P less than 0.02, student two-tail t-test). These results indicate that topical phenylephrine reached the RPE in vivo and prestimulated the alpha-1 adrenoreceptors.
兔视网膜色素上皮（RPE）具有一种α-1肾上腺素能受体，受到刺激时可显著降低RPE短路电流（Isc）。由于去氧肾上腺素是一种常用于散瞳的强效α肾上腺素能激动剂，我们研究了局部应用去氧肾上腺素散瞳对RPE转运的影响。未处理的黑色荷兰带兔在t = 0和t = 30分钟时各滴入一滴10%去氧肾上腺素，或在t = 30分钟时滴入一滴1%环喷托酯。在t = 50分钟时，将这些动物的RPE - 脉络膜 - 巩膜外植体密封于尤斯灌流小室中。在t = 60 - 70分钟时，向尤斯灌流小室两侧加入1.4×10⁻⁴ M肾上腺素。测量肾上腺素引起的Isc变化。接受去氧肾上腺素的兔Isc降低26%（±5%标准差，n = 6）。接受环喷托酯的兔Isc降低39%（±6%标准差，n = 5）。这些值有显著差异（P < 0.02，学生双尾t检验）。这些结果表明，局部应用的去氧肾上腺素在体内到达了RPE并预先刺激了α-1肾上腺素能受体。
