Mapping of Histamine H1 Receptors in the Human Brain Using [11C]Pyrilamine and Positron Emission Tomography

Kazuhiko Yanai, Takehiko Watanabe, Hiroyuki Yokoyama, Jun Hatazawa, Ren Iwata, Kiichi Ishiwata, Kenichi Meguro, Masatoshi Itoh, Toshihiro Takahashi, Tatsuo Ido, Taiju Matsuzawa

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52 Citations (Scopus)


We have studied the characteristics of carbon‐11 labeled pyrilamine as a radioligand for investigating histamine H1 receptors in human brain with positron emission tomography (PET). [11QPyrilamine is distributed evenly in proportion to cerebral blood flow at initial PET images. Later (after 45–60 min), 11C radioactivity was observed at high concentrations in the frontal and temporal cortex, hippocampus, and thalamus, and at low concentrations in the cerebellum and pons. The regional distribution of the carbon‐11 labeled compound in the brain corresponded well with that of the histamine H1 receptors determined in vitro in autopsied materials. In six controls, the frontal and temporal cortices/cerebellum ratio increased during the first 60 min to reach a value of 1.22 ± 0.071. Intravenous administration of d‐chlorpheniramine (5 mg) completely abolished the specific binding in vivo in the frontal cortex and temporal cortex (cortex/cerebellum ratio, 0.955 ±0.015). The availability of this method for measuring histamine H1 receptors in vivo in humans will facilitate studies on neurological and psychiatric disorders in which histamine H1 receptors are thought to be abnormal.

Original languageEnglish
Pages (from-to)128-136
Number of pages9
JournalJournal of Neurochemistry
Issue number1
Publication statusPublished - 1992 Jul


  • Histamine
  • Histamine H receptors
  • Human brain
  • In vivo study
  • Positron emission tomography
  • Pyrilamine

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience


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