Cellular localization of serotonin(2A) (5HT(2A)) receptors in the rat brain

The serotonin(2A) (5HT(2A)) receptors have been shown to play an important role in several psychiatric disorders, including depression, schizophrenia, and alcoholism, This immunohistochemical study examined the cellular local ization of 5HT(2A) receptors in various rat brain structures (olfactory, st riatum, cortex, hippocampus, and amygdala). The colocalization of 5HT(2A) r eceptors in astrocytes was performed by double-immunofluorescence staining of 5HT(2A) receptors and of glial fibrillary acidic protein (GFAP) using co nfocal laser microscopy, 5HT(2A) receptor immunolabeling was observed in ol factory bulbs, neostriatum, hippocampus, amygdala, and neocortex. Somata an d dendrites of pyramidal cells in the frontal cortex (layer V) were densely labeled with 5HT(2A) receptors. In several other brain structures (hippoca mpus, amygdala, striatum, olfactory structures), 5HT(2A) receptor immunolab eling was found in cell bodies and processes of neurons. 5HT(2A) receptor i mmunolabeling was also observed in GFAP-positive cells of the various brain structures we investigated (layers I/VI of the neocortex, corpus callosum, hippocampal fissure and hilus, and amygdala), These results indicate that 5HT(2A) receptors are expressed in neurons and astrocytes and suggest the p ossibility that not only neuronal but also glial 5HT(2A) receptors have fun ctional implications in psychiatric disorders. (C) 2000 Elsevier Science In c.