Taste effects of 'umami' substances in hamsters as studied by electrophysiological and conditioned taste aversion techniques

Takashi Yamamoto, Ryuji Matsuo, Yoshitaka Kiyomitsu, Ryuji Kitamura

Research output: Contribution to journalArticle

58 Citations (Scopus)

Abstract

Behavioral and electrophysiological experiments were performed to examine whether or not the taste of 'umami' substances such as monosodium glutamate (MSG), disodium 5′-inosinate (IMP), and disodium 5′-guanilate (GMP) is really unique in hamsters. When the animals were conditioned to avoid ingestion of MSG (or IMP) or their mixture by pairing its ingestion with an i.p. injection of LiCl, suppression of drinking generalized to IMP (or MSG), GMP, NaCl, and other sodium salts. Suppression of drinking after conditioning to NaCl generalized to MSG, IMP, GMP, and inorganic sodium salts. These learned aversions to umami substances and sodium salts were abolished by bilateral deafferentation of the chorda tympani, but were not affected by destruction of the bilateral glossopharyngeal nerves. The integrated whole-nerve responses of the chorda tympani to MSG, IMP, and NaCl were similar to each other, consisting of the initial dynamic phase and the following tonic phase. Synergism of chorda tympani responses to a mixture of MSG and IMP was not observed. Across-fiber response patterns of the chorda tympani for MSG, IMP, or their mixture were very similar to that for NaCl. Even the high concentrations of umami substances (0.3 M MSG, 0.3 M IMP, and the mixture) did not elicit any detectable responses in the glossopharyngeal nerve. These results suggest that the taste of umami substances is not unique in the hamster, but is similar to that of sodium salts, and is mediated exclusively via the chorda tympani.

Original languageEnglish
Pages (from-to)147-162
Number of pages16
JournalBrain Research
Volume451
Issue number1-2
DOIs
Publication statusPublished - Jun 7 1988

Keywords

  • Chorda tympani
  • Conditioned taste aversion
  • Glossopharyngeal nerve
  • Single fiber analysis
  • Taste quality
  • Umami

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology

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