Evidence for the presence of histamine uptake into the synaptosomes of rat brain

Eiko Sakurai, Eiichi Sakurai, L. Oreland, S. Nishiyama, M. Kato, T. Watanabe, Kazuhiko Yanai

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

Abstract

Histamine has many physiological roles in the brain and periphery. Neuronal histamine is metabolized almost exclusively by histamine N-methyltransferase. Although several neurotransmitter systems such as dopamine and 5-hydroxytryptamine have their specific reuptake system in their neurons and glial cells, a specific histamine reuptake system into the corresponding nerve terminals or glial cells has not yet been clearly elucidated. We characterized the uptake of histamine into the P2 fractions of rat brain homogenized in 0.32 mol/l sucrose using in vitro uptake techniques. [3H]histamine uptake increased with the increment of added protein amount and elapsed time. [ 3H]histamine uptake was also temperature-dependent. The uptake of [3H]histamine into the P2 fractions occurs by two saturable processes, a high-affinity and a low-affinity, characterized by Km values of 0.16 and 1.2 μmol/l, respectively. Na+, Cl- and HCO3- ions were essential for the uptake of histamine in P2 fractions. [3H]histamine uptake was inhibited in the presence of several tricyclic antidepressants. In accordance with this, the endogenous release of histamine from brain slices evoked by 100 mmol/l K+ was augmented in the presence of 20 μmol/l imipramine. These results further support the existence of a specific histamine uptake system in the brain, although the precise molecular entities have not been identified until now.

Original languageEnglish
Pages (from-to)72-80
Number of pages9
JournalPharmacology
Volume78
Issue number2
DOIs
Publication statusPublished - 2006 Oct

Keywords

  • Brain slices
  • Histamine
  • Histamine release
  • Putative histamine transporter
  • Rat brain
  • Reuptake inhibitor
  • Synaptosomes
  • Tricyclic antidepreesants
  • [ H]histamine uptake
  • [H]histamine uptake

ASJC Scopus subject areas

  • Pharmacology

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