title: Inhibitory effect of hippocampal 5-HT1A receptors on human explicit memory.
abstract: OBJECTIVE
  Recent studies have indicated that the serotonergic (5-HT) system plays important roles in memory function. However, the specific relationship between 5-HT(1A) receptors and memory function is not clear in the human brain. To clarify this relationship, the authors determined the availability of 5-HT(1A) receptors in the human brain and the relationship between regional receptor binding and memory function.
  
  
  METHODS
  Using positron emission tomography (PET) with [(11)C]WAY-100635, the authors examined 5-HT(1A) receptors and assessed their relationship with memory function. The 5-HT(1A )agonist tandospirone was then administered to investigate the effect of 5-HT(1A) receptor stimulation on cognitive function and neuroendocrinological response.
  
  
  RESULTS
  There was a significant negative correlation between explicit memory function and 5-HT(1A) receptor binding localized in the bilateral hippocampus where the postsynaptic 5-HT(1A) receptors are enriched. Furthermore, the administration of tandospirone dose-dependently impaired explicit verbal memory, while other cognitive functions showed no significant changes. The change in memory function paralleled those of body temperature and secretion of growth hormone, which were reported to be induced by the stimulation of postsynaptic 5-HT(1A) receptors.
  
  
  CONCLUSIONS
  Postsynaptic 5-HT(1A )receptors localized in the hippocampal formation have a negative influence on explicit memory function, which raises the possibility that the antagonistic effect of postsynaptic 5-HT(1A) receptors in the hippocampus leads to improvement of human memory function. Drugs that work as antagonists on postsynaptic 5-HT(1A) receptors may be favorable for improved control of memory impairment.
authors.affiliation: Brain Imaging Project, National Institute of Radiological Sciences, Chiba, Japan.
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Yasuno
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Suhara
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakayama
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Ichimiya
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Okubo
authors.forename: Akihiro
authors.initials: A
authors.lastname: Takano
authors.forename: Tomomichi
authors.initials: T
authors.lastname: Ando
authors.forename: Makoto
authors.initials: M
authors.lastname: Inoue
authors.forename: Jun
authors.initials: J
authors.lastname: Maeda
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Suzuki
mesh_terms: D000328:Adult; D001288:Attention / Q000187:drug effects / Q000502:physiology; D018592:Cross-Over Studies; D004311:Double-Blind Method; D006624:Hippocampus / Q000000981:diagnostic imaging / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D054833:Isoindoles; D008297:Male; D008568:Memory / Q000187:drug effects / Q000502:physiology*; D008875:Middle Aged; D010879:Piperazines / Q000494:pharmacology; D010919:Placebos; D011725:Pyridines; D011743:Pyrimidines / Q000494:pharmacology; D011985:Receptors, Serotonin / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D014055:Tomography, Emission-Computed; D014706:Verbal Learning / Q000187:drug effects / Q000502:physiology; D014888:Wechsler Scales
chemical_list: D054833:Isoindoles; D010879:Piperazines; D010919:Placebos; D011725:Pyridines; D011743:Pyrimidines; D011985:Receptors, Serotonin; D017366:Serotonin Receptor Agonists; C055267:tandospirone; C090413:N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-(2-pyridinyl)cyclohexanecarboxamide