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anesthetized, control SD rats. HMGB-1 peptide (dose and vehicle)
or vehicle alone was then applied to the dorsal surface of the
tongue, and CT responses to the same stimuli recorded. HMGB-1
application had no significant effect on CT response magnitudes.
We are currently testing whether local injection of HMGB-1
affects taste function, and the role of the peptide during taste
bud degeneration and regeneration. Acknowledgements:
NIDCD DC005811
#P169
POSTER SESSION IV:
CHEMICAL SIGNALING & BEHAVIOR;
PSYCHOPHYSICS; CHEMOSENSATION & DISEASE;
OLFACTION PERIPHERY; TASTE PERIPHERY
Taste on steroids: estrogen receptors are expressed in
type 2 taste cells
M. Rockwell Parker, Robert F. Margolskee
Monell Chemical Senses Center Philadelphia, PA, USA
Sex steroids can access the taste epithelium through three potential
routes: in the bloodstream, in saliva, or de novo within the taste cells
themselves. Among the sex steroids, 17β-estradiol affects the
broadest range of tissues in the body and plays a central role in the
function and maintenance of numerous sensory and metabolic
tissues. Estradiol exerts its effects through three different receptors:
ERα, ERβ, and GPER. Whether taste cells express any of these
receptors and thus directly respond to estradiol signaling was
previously unknown. Earlier work had suggested that taste
behaviors are affected when estradiol is absent, as evidenced by
psychophysical studies in women before and after menopause or in
female rats following gonadectomy. Using immunohistochemistry
and RT-PCR, we have found that type 2 taste cells in mice express
ERβ and GPER but not ERα. Further, ERβ is coexpressed more
often with T1R3 than with TRPM5, suggesting a role for this
receptor in the function of sweet- and umami-sensing cells. We are
currently determining whether estradiol treatment changes the ERβ
expression pattern in type 2 cells. Also, we will test whether
estradiol exposure modulates T1R mRNA expression levels.
Acknowledgements: This work was supported by NIDCD/NIH
funds (R01 DC03055 and T32 DC00014). Imaging was conducted
in Monell’s Histology and Cellular Localization Core supported by
NIDCD/NIH (P30 DC0011735) and NSF (DBI-0216310).
#P170
POSTER SESSION IV:
CHEMICAL SIGNALING & BEHAVIOR;
PSYCHOPHYSICS; CHEMOSENSATION & DISEASE;
OLFACTION PERIPHERY; TASTE PERIPHERY
Angiotensin II modulates taste sensitivities in mice
Noriatsu Shigemura, Tadahiro Ohkuri, Nao Horio,
Shusuke Iwata, Keiko Yasumatsu, Yuzo Ninomiya
Oral Neurosci., Grad. Sch. Dent. Sci., Kyushu Univ.
Fukuoka, Japan
Modulation of gustatory function critically influences food
preference, food intake and metabolic homeostasis. Even so, the
mechanisms for modulating taste sensitivity are poorly understood.
Here, we report that angiotensin II (AngII), which plays important
roles in the maintenance of sodium and water homeostasis,
modulates salt and sweet taste sensitivities in mice. The chorda
tympani nerve recording demonstrated that AngII suppresses
amiloride — sensitive taste responses to NaCl. Surprisingly, AngII
enhances sweet taste responses, without affecting responses to KCl,
sour, bitter and umami tastants. These effects of AngII on gustatory
nerve responses are blocked by AngII type1 receptor (AT1)
antagonist. Behavioral tests showed that lick rates (per 10sec) for
NaCl and sweeteners are significantly reduced by AT1 antagonist in
water deprived mice. Expression analyses revealed that AT1 are co-
expressed with αENaC (amiloride - sensitive epithelial sodium
channel α-subunit: a salt taste receptor) or T1r3 (a sweet taste
receptor component) in a subset of taste cells. These results suggest
that taste organ is a new peripheral target of AngII, and the specific
modulation of amiloride - sensitive salt and sweet taste sensitivities
may play an important role in regulating sodium and water intakes.
Acknowledgements: Grant-in-Aids 18791370 (N.S.), 18077004
(Y.N.), 18109013 (Y.N.) for Scientific Research from the Ministry
of Education, Culture, Sports, Science and Technology of Japan.
#P171
POSTER SESSION IV:
CHEMICAL SIGNALING & BEHAVIOR;
PSYCHOPHYSICS; CHEMOSENSATION & DISEASE;
OLFACTION PERIPHERY; TASTE PERIPHERY
Comparative Analysis of Taste-related Gene Expression
in Taste Papillae, Gut and Cell Lines
Jie Cao
1
, James Way
2
, Tymissha Jackson
2
, Jiang Xu
1
, Dana
Danger
2
, Chari Smith
2
, William Benson
3
, Steve Sparks
2
, Thomas
Rimele
4
, Channa Jayawickreme
4
, Liquan Huang
1
1
Monell Chemical Senses Center Philadelphia, PA, USA,
2
GlaxoSmithKline/Enteroendocrine Discovery Performance Unit
Research Triangle Park, NC, USA,
3
GlaxoSmithKline/Discovery
Technology, Platform Technology & Science Research Triangle
Park, NC, USA,
4
GlaxoSmithKline/Screening & Compound
Profiling, Platform Technology & Science Research Triangle
Park, NC, USA
G-protein-coupled taste receptors and their downstream signaling
components have been reported to be expressed not only in the oral
cavity but also in other tissues and cell lines. However, the exact
expression profiles of these genes in these tissues and cells are not
fully understood. In this study, we used conventional quantitative
real-time PCR and custom-made ABI TaqMan Low Desity Arrays
(TLDA cards) to determine the expression levels of these genes,
which include those for all 3 mouse T1r receptors, 35 T2r receptors,
α-gustducin, Gβ3, Gγ13, PLCβ2, TrpM5, 6 REEP proteins and 4
RTP proteins, GLP-1, peptide YY, neurotensin, and orphan receptors
GPRC5A, GPRC5B, GPRC5C, GPRC5D and GPRC6A. Mouse
fungiform papillae, circumvallate and foliate papillae, small and
large intestines, STC-1, GLUTag and MIN6 cells were used to
prepare RNA samples, which were reverse transcribed into first-
strand cDNAs using random primers. The results from the
quantitative assays indicated that only four of the 35
Tas2r
genes
were expressed in the fungiform whereas the expression of all
35 T
as2r
s was detected in the back of the tongue. The three cell
lines expressed a small subset of
Tas2r
s, a few of which were found
in all three cell lines. The expression of
Tas2r
genes was also
detected in mouse duodenum, jejunum, ileum, colon and rectum,
with the most abundance in the jejunum. The expression profiles
varied among the different intestinal segments; and within a
particular segment, a few genes were more strongly expressed than
others. Validation of these expression patterns using in situ
hybridization and immunohistochemistry is in progress.
Identification of the expressing cells for these taste-related genes
can provide insightful information underlying the function of these
genes in these tissues. Acknowledgements: Partially supported by a
grant from GlaxoSmithKline, and NIH grant R01 DC007487 to
L.H., and NIH-NIDCD Core Grant P30 DC011735 to R.Margolskee
and NSF Equipment Grant DBI-0216310 to N. Rawson.
84 | AChemS Abstracts 2012
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