Chemical Senses Advance Access originally published online on October 1, 2009
Chemical Senses 2009 34(9):809-818; doi:10.1093/chemse/bjp070
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Taste Preference and Nerve Response to 5'-Inosine Monophosphate Are Enhanced by Glutathione in Mice
1 Faculty of Health Science, Kio University, 4-2-2 Umami-naka, Koryo, Kitakatsuragi, Nara 635-0832, Japan 2 Graduate School of Human Sciences, Osaka University, 1-2 Yamadaoka, Suita, Osaka 565-0871, Japan 3 Department of Oral and Maxillofacial Surgery, Asahi University School of Dentistry, 1851 Hozumi, Mizuho, Gifu 501-0296, Japan 4 Department of Oral Physiology, Asahi University School of Dentistry, 1851 Hozumi, Mizuho, Gifu 501-0296, Japan 5 Present address: Information Administration Office, Product Information Department, Taiho Pharmaceutical Co., Ltd, 1-2-4 Kanda, Chiyoda-ku, Tokyo 101-0047 Japan
Correspondence to be sent to: Takashi Yamamoto, Faculty of Health Science, Kio University, 4-2-2 Umami-naka, Koryo, Kitakatsuragi, Nara 635-0832, Japan. e-mail: ta.yamamoto{at}kio.ac.jp
 |
Abstract |
|---|
Previous human sensory evaluation studies have shown that glutathione (GSH) enhances deliciousness, accompanied by thickness, mouthfulness, and continuity feeling, which is known as "kokumi" in Japanese, in an umami solution containing monosodium glutamate and 5'-inosine monophosphate (IMP). We conducted behavioral and electrophysiological experiments to explore possible interactions of taste effectiveness between GSH and umami substances in mice. The 2-bottle preference test revealed that the mice preferred GSH at concentrations ranging from 1 to 10 mM. When GSH was added to IMP or a mixture of IMP and monopotassium glutamate (MPG), the mice showed increased preference for these solutions over the individual IMP or the binary mixture of IMP and MPG in both short-term and long-term tests. The addition of GSH to MPG, however, did not increase preference. Neural responses of the chorda tympani and glossopharyngeal nerves to the mixture of IMP and GSH showed synergism, whereas synergism was not observed in the mixture of MPG and GSH in either taste nerve. Another behavioral study with the use of the conditioned taste aversion paradigm showed that aversions to MPG generalized moderately to GSH, but aversions to GSH did not generalize to MPG. The present study suggests that GSH enhances preference for umami solutions containing 5'-ribonucleotide rather than glutamate. On the basis of these results, we discuss possible receptors involved for the action of GSH.
Key words: electrophysiology, food additives, kokumi, preference, synergism, taste
Accepted 14 September 2009