A new research technique with the computerized radioluminographic imaging-plate system for receptors of neurotransmitters

受体放射自显影定量方法包括三项实验技术：1）受体功能位点的体外放射配基结合技术; 2）受体蛋白成熟位点的定量放射免疫组化技术; 3）受体产生位点的原位杂交技术。在此基础上，我们研究了内皮素（ET）受体的神经解剖分布。ET_A mRNA在脉络丛、室周器、口线核和二叠旁核中表达量很少，但在其中有明显表达。ET_B mRNA在脑桥核、脚间核、上级丘和小脑等脑区有大量表达。在最后区、孤束核和迷走神经核中观察到ET_A结合位点的独特定位。ET_A mRNA在脑干最后区呈离散分布，ET-3 mRNA表达丰富，ET_B mRNA结合位点广泛分布于脑干各处，ET_B mRNA表达丰富，连合核内可见ET_B mRNA表达的细胞团。小脑浦肯野细胞层具有丰富的ET_B结合位点，在该层星形胶质细胞Bergmann胶质细胞中检测到ET-3和ET_B mRNA。定量受体放射自显影方法应使研究人员阐明受体的神经递质的作用。

The quantitative receptor autoradiographic method with three experimental techniques, 1) in vitro radioligand-binding technique for functional sites of receptors, 2) quantitative radioimmunohistochemical technique for sites of receptor proteins maturation, and 3) in situ hybridization technique for production sites of receptors, have been developed to determine the precise location and kinetic properties of receptors for neurotransmitters. Based on the method, we investigated the neuroanatomical distribution of endothelin (ET) receptors. ET_A mRNA was of very few amount, but a significant expression was detected in the choroid plexus, circumventricular organ, oral linear nucleus and parabigeminal nucleus. There was a massive amount of ET_B mRNA expression, as seen in brain areas such as the pontine nucleus, interpeduncular nuclei, superior colliculus and cerebellum. A unique localization of ET_A binding sites was observed in the area postrema, solitary tract nucleus and vagal nucleus. ET_A mRNA was discretely localized in the area postrema, with rich ET-3 mRNA.ET_B binding sites were widely distributed throughout the brain stem, with rich ET_B mRNA.A cell-cluster with ET_B mRNA expression was noted in the commissural nucleus. Purkinje cell layr of the cerebellum had rich ET_B binding sites and ET-3 and ET_B mRNAs were observed in Bergmann glia, an astrocyte in the layr. The quantitative receptor autoradiographic method should enable investigators to elucidate the roles of receptors for neurotransmitters.