Identification of the 5-HT1A Receptor Binding Subunit in Rat Brain Membranes Using the Photoaffinity Probe [3H]8-Methoxy-2-[N-n-Propyl, N-3-(2-Nitro-4-Azidophenyl)Aminopropyl]Aminotetralin |
| |
Authors: | M B Emerit S El Mestikawy H Gozlan J M Cossery R Besselievre A Marquet M Hamon |
| |
Institution: | INSERM U. 288, Neurobiologie Cellulaire et Fonctionnelle, Facultéde Médecine Pitié-Salpêtrière, Pierre et Marie Curie, Paris;Laboratoire de Chimie Organique Biologique, UniversitéPierre et Marie Curie, Paris;Service des Molécules Marquées, CEA-Saclay, Gif-sur-Yvette, France |
| |
Abstract: | The synthesis of a tritiated derivative of the 5-HT1A photoaffinity probe 8-methoxy-2-N-n-propyl, N-3-(2-nitro-4-azidophenyl)aminopropyl]aminotetralin (3H]8-methoxy-3'-NAP-amino-PAT) allowed the use of this probe for attempting the irreversible labeling of specific binding sites in rat brain membranes. Sodium dodecyl-sulfate-polyacrylamide gel electrophoresis of proteins solubilized from hippocampal microsomal membranes that had been incubated with 20 nM 3H]8-methoxy-3'-NAP-amino-PAT under UV light revealed a marked incorporation of 3H label into a 63-kilodalton protein termed PI. As expected of a possible correspondence between PI and 5-HT1A receptor binding sites, 3H labeling by the photoaffinity probe could be prevented by selective 5-HT1A ligands such as 8-hydroxy-2-(di-n-propylamino)tetralin, ipsapirone, buspirone, and gepirone and by N-ethylmaleimide, but not by the 5-HT2 antagonist ketanserin, noradrenaline- and dopamine-related drugs, monoamine oxidase inhibitors, and chlorimipramine. Furthermore, the regional and subcellular distributions of PI were identical to those of specific 5-HT1A binding sites. These results indicated that the binding subunit of the 5-HT1A receptor is a 63-kilodalton protein with a functionally important sulfhydryl group(s). |
| |
Keywords: | Photoaffinity labeling 5-HT1A receptor [3H]8-Methoxy-2-[N-n-propyl N-3-(2-nitro-4-azidophenyl)aminopropyl]-aminotetralin Rat hippocampus |
|
|