ABSTRACT
While the results above suggest that the rat chorda tympani nerve becomes less sensitive to quinine with increasing age, others4 have recently shown that mouse chorda tympani nerve responses to quinine do not alter during development. When expressed relative to a 0.1 M NH4Cl reference response, mouse
chorda tympani responses to quinine are comparable between 7-to 10-d-old and 8 to 16-week-old animals. Similar findings have been reported for quinineelicited responses in the chorda tympani nerve of hamster at 14 to 20, 25 to 35, and 55 to 73 d of age.' When expressed relative to the response to 0.1 M NH4Cl, hamster chorda tympani responses to quinine remain stable with advancing age. Thus, the lack of consonance between these results and those of Yamada' most probably relates to the nature of the reference stimulus during development. That is, a changing reference stimulus (i.e., increasing NaCI sensitivity) can invoke an apparent fluctuation in peripheral taste system sensitivity to other stimuli. Although the developmental nature of NH4CI responses in mouse and hamster is not established, the rat chorda tympani does not alter in sensitivity to this taste stimulus.6
