Identification of (125I) endothelin-3 binding sites in the cochlea and the brain of guinea pig

Endothelin is involved in the tonus regulation of blood vessels and will be secreted by endothelial cells. The first isolation of endothelin was performed by Masaki et al. Endothelin is secreted in 3 isoforms. We preparated the cochlea and a median section of the brain from guinea pigs post mortem. The preparations were frozen at -20 deg C and sections performed. The sections were incubated with (125l) endothelin-3 for 75 mins. at -20 deg C with negative controls and exposed at -80 deg C. The same samples as described above concentrated and in 1:10 dilution were further transferred to sodium dodecyl sulfate polyacrylamid gel electrophoresis and later to a nitrocellulose membrane for immunoblot analysis. After staining and autoradiography we revealed a highly specific endothelin-3 binding at the brain sample and a homogenous binding in the cochlea sections