Abstracts - Association for Chemoreception Sciences

innervated by the trigeminal nerve and when stimulated evoke
protective airway reflexes such as sneezing, apnea and local
inflammation (Tizzano et al., 2010; AChemS 2012). We have
begun investigating SCCs in human sinonasal epithelium and
their clinical implications. Previously we and others reported
that cells resembling SCCs occur in human biopsy material
near the vestige of the vomeronasal organ (Braun et al., 2011)
as well as within the turbinates (Barham et al 2013; AChemS
2012). However, the exact distribution and abundance of SCCs
in humans is unknown. To map the distribution of SCCs, we
obtained middle and inferior turbinate mucosa from human
patients that were free of sinonasal disease, but were undergoing
surgical procedures requiring removal of this tissue. Whole
mount tissue was stained with antibodies against TRPM5 and
villin, which is expressed at the apex of microvillous, but not
ciliated, epithelial cells. TRPM5-immunoreactive cells were
scattered heterogeneously in the sinonasal tissue. The cells were
most abundant on the ridges of the turbinates and less abundant
on the lateral margins. Many TRPM5 immunoreactive cells
also labeled with the villin antibody, suggesting that TRPM5 is
present in microvillous but not ciliated cells of the epithelium.
Studies are in progress to determine if disease state alters the
distribution or abundance of these cells and whether SCCs in
humans are innervated by the trigeminal nerve, as in rodents.
Acknowledgements: R01 DC009820 (TEF and SCK) P30
DC04657 (to D. Restrepo)
#P116 POSTER SESSION III:
TRIGEMINAL; HUMAN OLFACTORY
PSYCHOPHYSICS; TASTE PERIPHERY
Responses to change in oral temperature by neurons in the
mouse medullary dorsal horn and nucleus of the solitary tract
Yi Kang, Christian Lemon
St. Louis University St. Louis, MO, USA
Psychophysical data show the temperature of sapid solutions
influences flavor. However, it is not entirely clear how central
neural circuits for oral sensation encode temperature input.
The trigeminal subnucleus caudalis (Vc) is a brainstem somatic
relay receiving temperature signals from the oro-facial region
and implicated for oral thermosensation. Additionally, the
solitary tract nucleus (NTS), the first central taste relay, also
receives thermal input from the mouth. Here we compared
neural responses of NTS and Vc to intraoral thermal stimulation
in anesthetized mice to assess the contribution of activity in
these structures to oral temperature responses in brain stem.
Extracellular single-unit activities of NTS thermo-gustatory
neurons and Vc thermo-somatic cells were recorded after
application of different temperature stimuli to tongue, including
cold (5 and 10 °C), cool/ambient (17 and 23 °C), and warm/
hot (30, 45, and 48 °C). Temperature stimulation was achieved
rapidly by oral flow of thermally varied water. Seventytwo
neurons were obtained; 34 from Vc and 38 from NTS.
Analyses revealed significant differences between NTS and
Vc in responses to thermal stimuli [F(1, 70) = 5.80, P ATP > acetylcholine
(ACh)). Because of the low percentage of ACh-sensitive MCs
and SCCs, ACh released from these cells may play a role in
paracrine regulation to influence neighboring cells. Using Ca 2+
imaging on intact epithelial preparations, we found that AChinduced
increases in intracellular Ca 2+ levels in epithelial cells
surrounding the MCs and SCCs were inhibited by muscarinic
ACh antagonist atropine. Our results suggest that MCs and
SCCs share common physiological roles in sensing chemical
stimuli and may release ACh to influence surrounding nonsensory
cells via paracrine mechanism. Because MCs lack
afferent innervation, this cholinergic paracrine regulation could
be especially important for chemoreception-mediated regulation
of MOE activities. Acknowledgements: Supported by research
grants NIH/NIDCD 009269, 012831 and ARRA administrative
supplement to WL
POSTER PRESENTATIONS
Abstracts are printed as submitted by the author(s).
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