Denis P, Dussaillant M, Nordmann J P, Elena P P, Saraux H, Rostene W
INSERM U339, Hôpital Saint Antoine, Paris, France.
Exp Eye Res. 1991 Mar;52(3):357-66. doi: 10.1016/0014-4835(91)90101-j.
Localization and pharmacological properties of vasoactive intestinal peptide (VIP) binding sites were investigated in eyes from albino rabbits and rats using an in vitro autoradiographic method. [125I]VIP was used as ligand, and various unlabelled peptides were studied to test the specificity of binding. Autoradiograms were generated by apposing 20-microns-thick cryostat eye sections to [3H]Hyperfilm or autoradiographic emulsion and quantified by means of image analysis procedures. Specific binding represented about 85% of total binding. Kinetic studies showed that equilibrium was reached after a 120-min incubation at room temperature. Biochemical investigations demonstrated that [125I-]VIP bound to a population of sites with high affinity (Kd = 2.27 +/- 0.25 nM). Inhibition of [125I]VIP binding with VIP and related peptides indicated the following rank order of potency: VIP greater than Peptide histidine isoleucine greater than secretin greater than human growth hormone-releasing factor, glucagon, VIP1-14, VIP14-28. In both species, specific binding was found in conjunctiva, iris, ciliary processes, choroid and retina. Moderate grain densities of VIP binding sites were also present in the rat cornea. Quantitative analysis of the autoradiograms revealed that the highest densities of [125I]VIP binding sites were located in the iris and ciliary epithelia in rabbits and in the inner retina in rats. Our findings suggest that VIP may play an important role in several ocular functions, especially in aqueous humor dynamics and retinal neuromodulation.
采用体外放射自显影法，研究了白化兔和大鼠眼中血管活性肠肽（VIP）结合位点的定位及药理学特性。以[125I]VIP作为配体，并研究了各种未标记的肽以测试结合的特异性。通过将20微米厚的低温恒温器眼切片与[3H]超敏胶片或放射自显影乳剂贴合来生成放射自显影片，并通过图像分析程序进行定量。特异性结合约占总结合的85%。动力学研究表明，在室温下孵育120分钟后达到平衡。生化研究表明，[125I-]VIP与一群具有高亲和力的位点结合（Kd = 2.27 +/- 0.25 nM）。用VIP和相关肽抑制[125I]VIP结合表明以下效价顺序：VIP大于肽组氨酸异亮氨酸大于促胰液素大于人生长激素释放因子、胰高血糖素、VIP1-14、VIP14-28。在这两个物种中，在结膜、虹膜、睫状体、脉络膜和视网膜中均发现特异性结合。大鼠角膜中也存在中等密度的VIP结合位点。放射自显影片的定量分析显示，[125I]VIP结合位点的最高密度位于兔的虹膜和睫状体上皮以及大鼠的视网膜内层。我们的研究结果表明，VIP可能在多种眼功能中起重要作用，尤其是在房水动力学和视网膜神经调节方面。
