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of stronger NaCl concentrations. The increased NaCl preferences
and decreased NaCl aversion in ENaC-KO mice indicate that the
ENaC-dependent mechanism is involved in perception of aversive
taste of NaCl. NaCl taste sensitivity was assessed by measuring
behavioral NaCl taste thresholds in mice with conditioned taste
aversion (CTA) formed to suprathreshold concentrations of LiCl.
ENaC-KO mice had elevated NaCl taste thresholds, which
indicates that the ENaC-dependent mechanism of salt taste is more
sensitive than the ENaC-independent mechanism retained in
ENaC-KO mice. Taste quality perception was examined using CTA
generalization between Na/Li and K salts. ENaC-KO mice
conditioned to avoid LiCl had stronger CTA generalization to KCl
than control mice. This indicates that the ENaC-dependent
mechanism is important for the ability to distinguish between Na/Li
and K salts and therefore is involved in perception of the Na/Li-
specific taste. Results of our study illustrate differences between the
ENaC-dependent and ENaC-independent salt taste mechanisms.
The latter is less sensitive and is involved in positive hedonic
responses and in detection of taste shared among Na/Li and K salts.
TMN and NPB contributed equally to this study.
#P157
POSTER SESSION IV:
CHEMICAL SIGNALING & BEHAVIOR;
PSYCHOPHYSICS; CHEMOSENSATION & DISEASE;
OLFACTION PERIPHERY; TASTE PERIPHERY
Changes in preference for amino acids by addition of glycogen
in C57BL/6 mice
Yuko Murata, Akemi Sakaguchi
National Research Inst. of Fisheries Science, Fisheries Research
Agency Yokohama, Japan
Various edible parts of shellfish contain the polysaccharide
glycogen and if its content is high, glycogen is thought to enhance
the palatability of the food. Although glycogen is tasteless and does
not directly contribute to the taste, it may have various interactive
effects enhancing the taste of amino acids. In this study, we
investigated changes in preference for 12 amino acids at 100mM
[except for aspartic acid (Asp) at 30mM] by addition of glycogen in
C57BL/6 mice using the 2-bottle preference test. No significant
preference for 0.1% glycogen alone was observed. The total intake
for methionine (Met) and taurine (Tau) was not significantly
different to distilled water (DW), while that for Asp, arginine (Arg),
lysine (Lys) and isoleucine (Ile) was significantly less and glycine
(Gly), alanine (Ala), serine (Ser), leucine (Leu), proline (Pro) and
valine (Val) was significantly more than DW. After addition of
glycogen, the total intake of Met changed to being less than DW
and it for Ile showed no difference to DW. However, preference
for Gly, Ala, Ser, Val and Ile significantly increased and Asp
significantly decreased after addition of glycogen. On the other
hand, preference for Arg, Leu, Lys, Met, Pro and Tau did not
significantly change after addition of glycogen. These results
suggest that addition of glycogen has varied effects on the
palatability of amino acids. Acknowledgements: Fisheries Research
Agency (Yokohama, Japan) research grant
#P158
POSTER SESSION IV:
CHEMICAL SIGNALING & BEHAVIOR;
PSYCHOPHYSICS; CHEMOSENSATION & DISEASE;
OLFACTION PERIPHERY; TASTE PERIPHERY
Pharmacological Modulation of Serotonin Reuptake and
5HT1A Receptors Has No Effect on Psychophysically
Determined Detection Thresholds of Taste Compounds by Rats
CM Mathes, AC Spector
Florida State University Deptartment of Psychology and Program
in Neuroscience Tallahassee, FL, USA
Serotonin (5HT) and 5HT1A receptors are found in taste buds.
Paroxetine (PAR), a selective serotonin reuptake inhibitor, has been
shown in humans to increase reported sensitivity to sucrose and
quinine, whereas WAY100635 (WAY), a 5HT1A-receptor
antagonist, has been shown in rats to inhibit chorda tympani
responses to NaCl, sucrose, and quinine. In the present report, we
used a 2-response taste detection task to measure the effect of
serotonergic drugs on the thresholds at which rats (n=3-8/tastant)
could discriminate decreasing concentrations of sucrose, NaCl,
citric acid, or quinine from water. After establishing psychometric
functions for each animal, 5 concentrations of each taste stimulus
were chosen to represent the dynamic portion of the taste-response
curve, and performance of the rats at these concentrations after
vehicle and drug injections was measured. We first tested PAR
(7 mg/kg ip), then WAY (0.3 mg/kg sc), and then implanted each
rat with a jugular catheter to test WAY again (1 mg/kg iv). When
analyzed via ANOVA, overall performance of the rats across all
concentrations dropped slightly when they were presented with: 1)
quinine after being injected with PAR ip or WAY sc, 2) NaCl after
PAR ip or WAY iv, and 3) sucrose after WAY iv. Despite these
differences, which, though significant, were minor at best, no
differences between drug and vehicle conditions were seen in the
asymptote or EC50 (threshold) of the psychometric function in the
curve parameter analysis. In contrast to findings in humans, our
results suggest that drugs that modulate 5HT activity have little
impact on taste detectability in rats, at least at these doses in this
task. In a rat model, serotonin’s paracrine action in the taste bud
may work in a manner that does not impact overt behavior involved
in taste detection. Acknowledgements: This work was supported in
part by NIDCD NRSA 1F32DC010517 to CMM.
#P159
POSTER SESSION IV:
CHEMICAL SIGNALING & BEHAVIOR;
PSYCHOPHYSICS; CHEMOSENSATION & DISEASE;
OLFACTION PERIPHERY; TASTE PERIPHERY
Adding Sucrose to Increase Bitter Taste Palatability
in Hamsters
Emily K. Lloyd, Bradley K. Formaker, Thomas P. Hettinger,
Marion E. Frank
University of Connecticut Health Center Farmington, CT, USA
Golden hamsters (
Mesocricetus auratus
) show an aversion to bitter
stimuli and a preference for sweet stimuli. Generally the aversion to
bitter stimuli is partially reversed by adding sucrose. Some bitter
stimuli are not rendered palatable by addition of sucrose, which
suggests that mechanisms for bitter detection can vary between
stimuli. We used 2-bottle 48-hr preference tests (R-L bottle
positions reversed after 24 hr) to measure intake of 12 solutions
compared to water. Solution to water preference ratios
(indifference = 0.5) were determined for 1mM quinine.HCl, 30µM
cycloheximide, 0.2mM chlorhexidine, 30mM caffeine, 10mM
80 | AChemS Abstracts 2012
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