YAMASHITA Kimihiro School of Medicine, Nagasaki University, Associate Professor, 医学部, 助教授 (50192399)
SHIGEMATSU Kazuto School of Medicine, Nagasaki University, Associate Professor, 医学部, 助教授 (20154205)
TANIYAMA Kohtaro School of Medicine, Nagasaki University, Professor, 医学部, 教授 (70030898)
KATAOKA Yasufumi School of Medicine, Kyushu University, Associate Professor, 医学部, 助教授 (70136513)
|Budget Amount *help
¥6,400,000 (Direct Cost : ¥6,400,000)
Fiscal Year 1996 : ¥1,600,000 (Direct Cost : ¥1,600,000)
Fiscal Year 1995 : ¥4,800,000 (Direct Cost : ¥4,800,000)
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.
ラット下垂体、延髄弧束核におけるエンドセリンET_A型とET_B型受容体の発現と特性、ラット胎盤におけるET_A型とET_B型受容体の機能的成熟と、それぞれの発現部位を同定した。とくに、ラット延髄下部では、area postrema,nucleus solitary tract,dorsal motor nucleus of vagus,hypoglossal nuclelusにET_B活性が存在した。腹側では、lateral reticular nucleusに限局的に密着していた。nucleus spinal tract trigeminal nerveにも存在した。ET_A活性は、area postrema,nucleus solitary tract,dorsal motor nucleus of vagusに孤立的に検出された。ET_BmRNAは、ET_B活性の分布と一致していたが、発現量は必ずしも結合活性量と相関しなかった。ET_A受容体mRNAは、area postremaに限局的に認められた。