GABAA receptors : Immunocytochemical distribution of 13 subunits in the adult rat brain

摘要: Abstract GABAA receptors are ligand-operated chloride channels assembled from five subunits in a heteropentameric manner. Using immunocytochemistry, we investigated the distribution of receptor deriving 13 different genes (α1–α6, β1–β3, γ1–γ3 and δ) adult rat brain. Subunit α1-, β1-, β2-, β3- γ2-immunoreactivities were found throughout brain, although differences their observed. α2-, α3-, α4-, α5-, α6-, γ1- δ-immunoreactivities more confined to certain brain areas. Thus, α2-subunit-immunoreactivity was preferentially located forebrain areas cerebellum. α6-immunoreactivity only present granule cells cerebellum cochlear nucleus, subunit γ1-immunoreactivity central medial amygdaloid nuclei, pallidal areas, substantia nigra pars reticulata inferior olive. The α5-subunit-immunoreactivity strongest Ammon’s horn, olfactory bulb hypothalamus. In contrast, α4-subunit-immunoreactivity detected thalamus, dentate gyrus, tubercle basal ganglia. α3-immunoreactivity observed glomerular external plexiform layers bulb, inner cerebral cortex, reticular thalamic zonal superficial superior colliculus, amygdala cranial nerve nuclei. Only faint γ3-immunoreactivity most areas; it darkest midbrain pontine δ-immunoreactivity frequently co-distributed with α4 subunit-immunoreactivity, e.g. striatum, outer cortex molecular layer. Striking examples complementary subunit-immunoreactivities considerably concentrated neostriatum than pallidum entopeduncular nucleus. labeling for γ2-subunits prevailed compared striatum. With exception which prominently stained α3, β1, β3 γ2, nuclei rich β2- δ-immunoreactivities. Whereas dorsal lateral geniculate nucleus strongly immunoreactive α4, β2 δ, ventral predominantly labeled α2, γ2; α1- α5-immunoreactivities about equally distributed both hypothalamic immunoreactivities α1, supraoptic staining conspicuous dendritic networks β2, γ2 antibodies contrasted by perykarya β1- Among all regions, median emminence heavily β2-immunoreactivity. medulla, strong, whereas olive significantly γ1 γ2. this study, highly heterogeneous This apparently typical patterns co-distribution these support assumption multiple, differently subtypes within