Frambach D A, Valentine J L, Weiter J J
Eye Research Institute of Retina Foundation, Boston, Massachusetts.
Invest Ophthalmol Vis Sci. 1988 May;29(5):737-41.
Retinal pigment epithelium (RPE)-choroid-sclera preparations from black, dutch-belted rabbits were sealed in an Ussing chamber. The RPE-generated trans-RPE voltage (Ve) and electrical resistance (R) were monitored. Epinephrine (an alpha and beta adrenergic agonist) reduced Ve by as much as 39% without affecting R. A response to epinephrine was noted at concentrations as low as 1.4 X 10(-7) M. Phenylephrine (an alpha adrenergic agonist) had essentially the same effect as epinephrine at identical concentrations. Clonidine (an alpha-2 adrenergic agonist) had a very slight effect but only at 10(-4) M. Isoproterenol (a beta adrenergic agonist) had no apparent effect upon Ve or R. The RPE response to epinephrine and phenylephrine was blocked by the alpha adrenergic antagonist phentolamine and by the alpha-1 adrenergic antagonist prazosin but not by the alpha-2 adrenergic antagonist yohimbine or by the beta adrenergic antagonist propranolol. Dibutyryl cyclic AMP (in the presence and absence of IBMX) and cyclic GMP (as cGMP and in the dibutyryl form) had no apparent effect upon Ve or R. These results indicate that rabbit RPE possesses an alpha-1 adrenoreceptor which, when stimulated, substantially reduces the RPE generated trans-RPE electrical current.
将来自黑色荷兰带兔的视网膜色素上皮（RPE）-脉络膜-巩膜制剂密封在尤斯灌流小室中。监测RPE产生的跨RPE电压（Ve）和电阻（R）。肾上腺素（一种α和β肾上腺素能激动剂）可使Ve降低多达39%，而不影响R。在低至1.4×10（-7）M的浓度下即可观察到对肾上腺素的反应。去氧肾上腺素（一种α肾上腺素能激动剂）在相同浓度下与肾上腺素具有基本相同的作用。可乐定（一种α-2肾上腺素能激动剂）只有在10（-4）M时才有非常轻微的作用。异丙肾上腺素（一种β肾上腺素能激动剂）对Ve或R没有明显影响。RPE对肾上腺素和去氧肾上腺素的反应被α肾上腺素能拮抗剂酚妥拉明和α-1肾上腺素能拮抗剂哌唑嗪阻断，但未被α-2肾上腺素能拮抗剂育亨宾或β肾上腺素能拮抗剂普萘洛尔阻断。二丁酰环磷酸腺苷（在有和没有异丁基甲基黄嘌呤的情况下）和环磷酸鸟苷（以cGMP和二丁酰形式）对Ve或R没有明显影响。这些结果表明，兔RPE具有α-1肾上腺素能受体，当受到刺激时，该受体可显著降低RPE产生的跨RPE电流。
