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dependent manner. In contrast, odorants that otherwise were
relatively strong agonists for the ORN being tested were PI3K-
independent. Two very dissimilar complex odorants, Symrise-100
and Henkel-100, both showed PI3K-dependent enhancement of the
response to the mixture, providing further support for there being
an extensive repertoire of PI3K-dependent ligands. Collectively,
these findings argue that many different odorants are PI3K-
dependent antagonists in mixture and as such create a broad basis
for opponent coding in mammalian ORNs. Acknowledgements:
NIDCD DC001655, DC005995
#P166
POSTER SESSION IV:
CHEMICAL SIGNALING & BEHAVIOR;
PSYCHOPHYSICS; CHEMOSENSATION & DISEASE;
OLFACTION PERIPHERY; TASTE PERIPHERY
Comparison of the intrinsic odor response and response
imposed by aerodynamics in the rat olfactory epithelium
John W Scott, Lisa Sherrill
Emory University, Department of Cell Biology Atlanta, GA, USA
The olfactory epithelium intrinsic response is determined primarily
by the specificity of olfactory receptors. Epithelial odorant access is
controlled by air flow rate and sorption onto upstream surfaces in
the intact nose so that responses for many water soluble odorants
are strongest in the dorsomedial region of high air flow rate. We
compared the EOG distribution (the relative response size in the
medial vs.lateral regions) to the Henry law constant (HLC), which
describes air/water partitioning of compounds (values from EPI
suite at EPA.gov, with units of atm-m
3
/M). For a broad range of
HLC (from 5.15, the value for decane, to 2.0x10
-5
, near the value
for benzaldehyde) the response distribution correlates with the
log(HLC) in two intact nose experiments (R= -0.82, p<.001, N=45
odorants) and (R= -.74, p<.001, N=38). This was also seen in our
published study of the intrinsic response with an opened epithelium
(R= -.79, p<.001, N=34). For values of HLC between 2.75x10
-5
and
6.5x10
-7
, the correlation for intact experiments is weaker (R= .50,
p<.05, N=21 & R= .30, NS, N=13) and reversed. This range
includes alcohols, carboxylic acids, vanillin, ethylacetoacetate, and
pyrazine. Similar results occurred with other measures of odorant
solubility or polarity. New open epithelium recordings with six
extremely soluble odorants from this group confirm that their
intrinsic response does not strongly favor the region of high airflow
in either the intact or open epithelium. These results show that the
relationship between physical chemical properties and response
distribution in the rat epithelium is nonlinear, probably due to
extreme upstream sorption of some odorants. The result may
explain some (but not all) of the apparent discrepancies between
epithelial recordings and observations in olfactory bulb.
Acknowledgements: Supported by NIH grant DC 008648
#P167
POSTER SESSION IV:
CHEMICAL SIGNALING & BEHAVIOR;
PSYCHOPHYSICS; CHEMOSENSATION & DISEASE;
OLFACTION PERIPHERY; TASTE PERIPHERY
Electroolfactorgram recording from the human olfactory
epithelium during natural nasal respiration
Anton Plotkin, Anat Arzi, Sagit Shushan, Noam Sobel
Weizmann Institute of Science/Department of Neurobiology
Rehovot, Israel
The olfactory system presents a unique opportunity to directly
record neural activity in humans in vivo. Olfactory receptor
neurons (ORNs), a form of PNS-CNS transition neurons outside
the skull, located in the olfactory epithelium, enable in vivo
recording of olfactory responses from awake behaving humans.
Till now, the work frame for EOlfG research was recording during
short respiration cessation to avoid the ORNs response to the
airflow overshadowing the olfactory evoked response. Because the
sniff is an integral part of the olfactory perception, its absence may
alter or even abolish the ORNs response. Here we set out to
develop a method for EOlfG recording during natural human nasal
respiration. EolfG’s were recorded at 1 kHz from a normosmic
healthy subject (M, age = 25) using Ag/AgCl electrode coated with
Teflon tubing (0.8 mm OD) filled with Ringer-agar (1%). Using a
computer-controlled olfactometer we delivered an odorant
(L-bronyl Acetate, CAS 5655-61-8) into the recorded nostril via
Teflon tubing (inner diameter = 2.15 mm), maintaining steady
mechanical and thermal conditions (5.5 SLPM, 37 °C, 80% RH).
Stimulus duration was 0.5 s, and inter-stimulus-interval was 25 s.
The experimental paradigm contained four blocks; each consisted
of five-odorant presentations during respiration cessation and five
presentations during natural respiration. We found that a simple
high-pass filtering with the corner frequency of 1 Hz enabled on-
line visualization of the EolgG recorded during natural breathing.
Moreover, a more advanced signal processing method almost
completely reconstructs the olfactory portion of the recorded
EOlfG, which enables the recording of in vivo ORNs activity and
perception simultaneously in naturally breathing humans.
Acknowledgements: Supported by ERC Ideas 800250
#P168
POSTER SESSION IV:
CHEMICAL SIGNALING & BEHAVIOR;
PSYCHOPHYSICS; CHEMOSENSATION & DISEASE;
OLFACTION PERIPHERY; TASTE PERIPHERY
HMGB-1 expression in the normal and injured peripheral
taste system
Caitlin M Madigan, Lynnette P McCluskey
Georgia Health Sciences University Augusta, GA, USA
High-mobility group protein (HMGB)-1 is a ubiquitous nuclear
protein that acts as a danger signal when released from injured or
infected cells. We explored HMGB-1 expression in the normal
peripheral taste system and after chorda tympani nerve (CT)
sectioning. HMGB-1 is robustly expressed in the cytosol of most
taste receptor cells, and in macrophages responding to CT injury.
At day 1 post-sectioning, HMGB-1 expression is reduced in
denervated vs. contralateral or sham taste buds. This suggests that
degenerating taste receptor cells secrete cytosolic HMGB-1.
Released HMGB-1 may then act through the toll-like receptor
(TLR)-4 present on taste receptor cells and modulate taste function.
We determined whether lingual application of recombinant HMGB-
1 peptide (to mimic the physiological release of HMGB1 after
injury) alters CT responses. We measured baseline CT responses in
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