1979 Volume 21 Issue 1 Pages 35-40
Effects of an early experience with a gustatory stimulus on later sensitivity to that stimulus was studied in 36 rats. A quinine hydrochloride (Q-HCl) solution (10-3 M) or deionized water (D. W.) was directly applied to the tongue every day for 20 days starting from the age of two days postnatally. In a 2-bottle choice between Q-HCl and D.W. at the age of 39 days, the Q-HCl stimulated rats avoided a lower concentration of Q-HCl than that avoided by the D. W. stimulated rats. Rats similarly stimulated with Q-HCl for 20 days, but started from the age of 31 days, and tested at 67 days postnatally, did not reject the concentration of Q-HCl avoided by the rats stimulated before weaning. The results suggest that a gustatory stimulus frequently given in a preweaning period enhances the sensitivity to that stimulus at a later time, but that the same stimulus given after weaning fails to produce such an effect.