Abstracts - Association for Chemoreception Sciences

P O S T E R S
typically 40-minute session of 200-400 trials. After acquisition of
this task novel stimuli are also presented at the manifold after
which rats are rewarded at any spout of their choice. The spatial
response pattern directly reflects the similarity of the novel
stimulus to the acquired training set of tastants. Four rats were
successfully trained, achieving 60-80% accuracy after 130 days of
training. Controls confirmed rats used taste cues to guide their
responses. One of the rats showed deviant responses, which
ultimately converged with those of the other rats. All rats showed
clear concentration-response functions (0, 3,10, 33, 100 and 300%
of conc. of train stimuli), which were stable across test sessions.
Generalization to novel tastants was also evaluated. Rats can learn
to associate tastes with locations, which can be used to investigate
their perception of taste quality and intensity of novel stimuli.
Acknowledgements: Supported by R01 DC009994-01
#P182 POSTER SESSION IV: CHEMOSENSORY
TRANSDUCTION AND SIGNALING
Behavioral and anatomical characterization of sucralose
preferring and avoiding rats
Gregory C Loney, Ann Marie Torregrossa, Lisa A Eckel
Florida State University Tallahassee, FL, USA
Rats display a bimodal preference for the non-nutritive sweetener
sucralose. While some prefer sucralose over water across a range
of concentrations, others avoid sucralose at concentrations above
0.1 g/L. While this phenomenon has been studied primarily in
males, there is some evidence that females may differ from males
in their preference for sucralose. Currently, the mechanism
underlying individual differences in sucralose preference in either
sex is poorly understood, but some data suggest that it may be
related to individual differences in sensitivity to a bitter taste
quality of sucralose. In humans, increased sensitivity to bitter
substances appears to be positively correlated with the number of
fungiform papillae counted on the surface of the tongue. The goal
of the present study was to determine whether preference for
sucralose is influenced by sex and/or the number of fungiform
papillae on the rat’s tongue. Male and female rats (n=22/sex) were
given access to ascending concentrations of sucralose (0.0001 - 2.0
g/L) and water in two-bottle, 24-h preference tests. While a
greater proportion of males than females were characterized as
sucralose preferrers (40% vs 30%), once categorized, we found no
sex difference in their preference curves. The tongues of a subset
of these rats (10 preferrers; 11 avoiders) were incised just anterior
to the median molar eminence, stained with methylene blue, and
the number of fungiform papillae with clear taste pores was
counted. Sucralose avoiders had significantly more papillae than
did sucralose preferrers (109±4 vs 95±5, respectively, t(19)=2.18,
p