5-HT1A receptor expression in pyramidal neurons of cortical and limbic brain regions

Cell Tissue Res. 2005 Aug;321(2):159-72. doi: 10.1007/s00441-005-1112-x. Epub 2005 Jun 10.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 8-Hydroxy-2-(di-n-propylamino)tetralin / metabolism
  • Animals
  • Basal Ganglia / cytology
  • Basal Ganglia / metabolism
  • Binding, Competitive / physiology
  • Calcium-Binding Proteins / metabolism
  • Cerebral Cortex / cytology
  • Cerebral Cortex / metabolism*
  • Gene Expression / physiology
  • Glutamic Acid / metabolism
  • Hippocampus / cytology
  • Hippocampus / metabolism
  • Interneurons / cytology
  • Interneurons / metabolism
  • Limbic System / cytology
  • Limbic System / metabolism*
  • Male
  • Pyramidal Cells / cytology
  • Pyramidal Cells / metabolism*
  • RNA, Messenger / metabolism
  • Radioligand Assay
  • Receptor, Serotonin, 5-HT1A / genetics
  • Receptor, Serotonin, 5-HT1A / metabolism*
  • Serotonin / metabolism*
  • Serotonin Receptor Agonists / metabolism
  • Synaptic Transmission / physiology*
  • Tupaia
  • gamma-Aminobutyric Acid / metabolism


  • Calcium-Binding Proteins
  • RNA, Messenger
  • Serotonin Receptor Agonists
  • Receptor, Serotonin, 5-HT1A
  • Serotonin
  • Glutamic Acid
  • gamma-Aminobutyric Acid
  • 8-Hydroxy-2-(di-n-propylamino)tetralin