title: 5-HT1A receptor expression in pyramidal neurons of cortical and limbic brain regions.
abstract: We studied expression of the 5-HT(1A) receptor in cortical and limbic areas of the brain of the tree shrew. In situ hybridization with a receptor-specific probe and immunocytochemistry with various antibodies was used to identify distinct neurons expressing the receptor. In vitro receptor autoradiography with (3)H-8-OH-DPAT ((3)H-8-hydroxy-2-[di-n-propylamino]tetralin) was performed to visualize receptor-binding sites. In the prefrontal, insular, and occipital cortex, 5-HT(1A) receptor mRNA was expressed in pyramidal neurons of layer 2, whereas (3)H-8-OH-DPAT labeled layers 1 and 2 generating a columnar-like pattern in the prefrontal and occipital cortex. In the striate and ventral occipital cortex, receptor mRNA was present within layers 5 and 6 in pyramidal neurons and Meynert cells. Pyramid-like neurons in the claustrum and anterior olfactory nucleus also expressed the receptor. Principal neurons in hippocampal region CA1 expressed 5-HT(1A) receptor mRNA, and (3)H-8-OH-DPAT labeled both the stratum oriens and stratum radiatum. CA3 pyramidal neurons displayed low 5-HT(1A) receptor expression, whereas granule neurons in the dentate gyrus revealed moderate expression of this receptor. In the amygdala, large pyramid-like neurons in the basal magnocellular nucleus strongly expressed the receptor. Immunocytochemistry with antibodies against parvalbumin, calbindin, and gamma aminobutyric acid (GABA) provided no evidence for 5-HT(1A) receptor expression in GABAergic neurons in cortical and limbic brain areas. Our data agree with previous findings showing that the 5-HT(1A) receptor mediates the modulation of glutamatergic neurons. Expression in the limbic and cortical areas suggested an involvement of 5-HT(1A) receptors in emotional and cognitive processes.
authors.affiliation: Clinical Neurobiology Laboratory, German Primate Center, Göttingen.
authors.forename: Monika
authors.initials: M
authors.lastname: Palchaudhuri
authors.forename: Gabriele
authors.initials: G
authors.lastname: Flügge
mesh_terms: D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000378:metabolism; D000818:Animals; D001479:Basal Ganglia / Q000166:cytology / Q000378:metabolism; D001667:Binding, Competitive / Q000502:physiology; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002540:Cerebral Cortex / Q000166:cytology / Q000378:metabolism*; D015870:Gene Expression / Q000502:physiology; D018698:Glutamic Acid / Q000378:metabolism; D006624:Hippocampus / Q000166:cytology / Q000378:metabolism; D007395:Interneurons / Q000166:cytology / Q000378:metabolism; D008032:Limbic System / Q000166:cytology / Q000378:metabolism*; D008297:Male; D017966:Pyramidal Cells / Q000166:cytology / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D011869:Radioligand Assay; D044282:Receptor, Serotonin, 5-HT1A / Q000235:genetics / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism*; D017366:Serotonin Receptor Agonists / Q000378:metabolism; D009435:Synaptic Transmission / Q000502:physiology*; D014417:Tupaia; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D002135:Calcium-Binding Proteins; D012333:RNA, Messenger; D017366:Serotonin Receptor Agonists; D044282:Receptor, Serotonin, 5-HT1A; D012701:Serotonin; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin