Kalapesi F B, Coroneo M T, Hill M A
Department of Anatomy, University of New South Wales, Sydney NSW 2052, Australia.
Br J Ophthalmol. 2005 Jun;89(6):758-63. doi: 10.1136/bjo.2004.053025.
BACKGROUND/AIM: Alpha-2alpha adrenergic receptor (alpha(2)-AR) agonists are thought to be neuroprotective, preventing retinal ganglion cell death independent of pressure reduction. Previous studies have identified alpha(2)-ARs in rat retina. The authors aimed to demonstrate the presence and localisation of alpha(2)-ARs in human and rat retina and on the rat retinal ganglion cell line, RGC-5.
Seven postmortem human and three postmortem rat eyes were paraformaldehyde fixed and frozen. RGC-5 cells were also paraformaldehyde fixed. The expression of alpha(2A)-ARs was determined by antibody immunofluorescence.
alpha(2A)-AR expression was identified in the human retina, on ganglion cells, and cells in the inner and outer nuclear layers (INL, ONL). Differential alpha(2A)-AR staining patterns in the INL and ONL suggest a further restriction to as yet unidentified neuronal subclasses. The RGC-5 cell line also expressed alpha(2A)-ARs in undifferentiated cells and an increased expression upon fully differentiated cells.
alpha(2)-AR agonists in addition to their pressure lowering effects in the eye, may act directly upon retinal neurons, including retinal ganglion cells. The presence of alpha(2)-ARs on the RGC-5 cell line allows future investigation of these possible direct effects using in vitro glaucoma model systems.
背景/目的：α2α肾上腺素能受体（α2-AR）激动剂被认为具有神经保护作用，可独立于降压作用预防视网膜神经节细胞死亡。先前的研究已在大鼠视网膜中鉴定出α2-AR。作者旨在证明α2-AR在人和大鼠视网膜以及大鼠视网膜神经节细胞系RGC-5中的存在和定位。
7只人死后眼球和3只大鼠死后眼球用多聚甲醛固定并冷冻。RGC-5细胞也用多聚甲醛固定。通过抗体免疫荧光法测定α2A-AR的表达。
在人视网膜的神经节细胞以及内核层和外核层（INL、ONL）的细胞中鉴定出α2A-AR表达。INL和ONL中不同的α2A-AR染色模式表明其进一步局限于尚未确定的神经元亚类。RGC-5细胞系在未分化细胞中也表达α2A-AR，在完全分化的细胞中表达增加。
α2-AR激动剂除了在眼中具有降压作用外，可能还直接作用于视网膜神经元，包括视网膜神经节细胞。RGC-5细胞系上α2-AR的存在使得未来可以使用体外青光眼模型系统研究这些可能的直接作用。
