Quantitative autoradiography of beta-1 and beta-2 adrenergic receptor and cellular localization of mRNA for beta-1 adrenergic receptor in rat brain

Abstract

We have used both quantitative autoradiography to localize in rat brain beta-1 and beta-2 adrenergic receptors and in situ hybridization to detect expression of beta-1 adrenergic receptor mRNA in rat brain. The receptors were labeled in vitro with 3H-dihydroalprenolol (3H-DIIA) that binds nonselectively to both beta-1 and beta-2 receptor subtypes. Selective inhibition of 3H-DHA binding with specific antagonists of beta-1 and beta-2 receptors allowed the visualization of beta-adrenergic receptor subtypes. High levels of beta-1 receptors were observed in the cingulate cortex, layers I-III of the cerebral cortex, hippocampus, and thalamus. Oligonucleotide labeled with 35S-dATP was used for in situ hybridization. High levels of beta-2 receptors were found in the cerebellum. Approximately equal levels of beta-1 and beta-2 receptors occurred in the midbrain including substantia nigra. The hybridization signal for beta-1 mRNA was strongest in cingulate and piriform cortex, thalamic nuclei and light or moderate in somatosensory cortex and hippocampus. The pronounced differences in the ratio of beta-1 to beta-2 receptors among brain .regions suggests that the subtypes of beta-adrenergic receptors may play different roles in neuronal function. © 1996 The Korean Society for Molecular Biology.