Hypothalamic histamine release by taste stimuli in freely moving rats: Possible implication of palatability

Yada Treesukosol, Tomoko Ishizuka, Chizuko Yamamoto, Kanae Senda, Shintaro Tsutsumi, Atsushi Yamatodani, Takashi Yamamoto

Research output: Contribution to journalArticlepeer-review


Our previous study indicated that taste information via the chorda tympani (CT) activates the central histaminergic system in anesthetized rats. However, the physiological roles of taste-induced histamine release remain unknown, thus to further investigate the relationship between histamine release and gustatory information, in the present study we investigated the effect of taste stimuli infused intraorally on histamine release using in vivo microdialysis in free moving rats. Consistent with findings from our previous study, application of NaCl and HCl caused significant increases in histamine levels further supporting the suggestion that this phenomenon is attributed to the excitation of the CT. When rats were intraorally infused with quinine HCl (QHCl) solution, a significant increase in hypothalamic histamine release was observed. On the other hand, histamine release was decreased by sucrose and saccharin solutions. When rats were conditioned to acquire taste aversion to sucrose solution or saccharin solution, instead of the histamine decrease seen by the palatable solutions, the pattern of histamine release was similar to that seen by QHCl solution. From these observations, it is concluded that the histamine release by the infusion of these tastants may be explained by two mechanisms - by causing a transient increase after taste stimulation and by causing a decrease relative to the tastant's palatability.

Original languageEnglish (US)
Pages (from-to)67-72
Number of pages6
JournalBehavioural Brain Research
Issue number1
StatePublished - Oct 14 2005


  • Anterior hypothalamus
  • Histamine
  • Microdialysis
  • Palatability
  • Taste
  • Taste aversion

ASJC Scopus subject areas

  • Behavioral Neuroscience


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