Taste preference changes throughout different life stages in male rats

PLoS One. 2017 Jul 25;12(7):e0181650. doi: 10.1371/journal.pone.0181650. eCollection 2017.

Abstract

Taste preference, a key component of food choice, changes with aging. However, it remains unclear how this occurs. To determine differences in taste preference between rats in different life stages, we examined the consumption of taste solutions and water using a two-bottle test. Male Sprague-Dawley rats of different ages were used: juvenile (3-6 weeks), young adult (8-11 weeks), adult (17-20 weeks), middle-aged (34-37 weeks), and old-aged (69-72 weeks). The intakes of the high and low concentration solutions presented simultaneously were measured. We observed that the old-aged group had lower preference ratios for 0.3 M sucrose and 0.1 M MSG in comparison with other groups. The preference ratio for 0.03 mM QHCl was higher in the middle-aged group than in the three younger groups and higher in the old-aged group than the juvenile group. The taste preferences for HCl and NaCl did not significantly differ among the age groups. The old-aged group tended to prefer high concentrations of sucrose, QHCl, NaCl, and MSG to low concentrations, indicating age-related decline in taste sensitivity. We also aimed to investigate differences between life stages in the electrophysiological responses of the chorda tympani nerve, one of the peripheral gustatory nerves, to taste stimuli. The electrophysiological recordings showed that aging did not alter the function of the chorda tympani nerve. This study showed that aging induced alterations in taste preference. It is likely that these alterations are a result of functional changes in other peripheral taste nerves, the gastrointestinal system, or the central nervous system.

MeSH terms

  • Aging / physiology*
  • Aging / psychology
  • Animals
  • Chorda Tympani Nerve / physiology
  • Electrophysiology
  • Male
  • Quinine
  • Rats
  • Rats, Sprague-Dawley
  • Sodium Chloride
  • Sucrose
  • Taste / physiology*

Substances

  • Sodium Chloride
  • Sucrose
  • Quinine

Grants and funding

This work was supported by a grant from the Mishima Kaiun Memorial Foundation and Grants-in-Aid for Young Scientists (B) (No. 23792136) to C IY from the Ministry of Education, Culture, Sports, Science and Technology of Japan.