Abstracts - Association for Chemoreception Sciences

#P113 POSTER SESSION II:
OLFACTION DEVELOPMENT; TASTE CNS;
NEUROIMAGING; OLFACTION CNS
#P114 POSTER SESSION III:
TRIGEMINAL; HUMAN OLFACTORY
PSYCHOPHYSICS; TASTE PERIPHERY
DIFFERENTIAL MODIFICATIONS OF SYNAPTIC
WEIGHTS DURING ODOR RULE LEARNING:
DYNAMICS OF INTERACTION BETWEEN THE
PIRIFORM CORTEX WITH LOWER AND HIGHER
BRAIN AREAS
Yaniv Cohen 1,2,3 , Donald A. Wilson 2,3 , Edi Barkai 1
1
Departments of Biology and Neurobiology, Faculty of Natural Sciences,
University of Haifa Haifa, Israel, 2 Department of Child and Adolescent
Psychiatry, New York University Langone School of Medicine New
York, NY, USA, 3 Emotional Brain Institute, Nathan Kline Institute for
Psychiatric Research, Orangeburg New York, NY, USA
Learning of a particularly difficult olfactory-discrimination (OD)
task results in acquisition of rule-learning, a process that requires
prolonged and extensive training. Previously, we demonstrated
enhanced synaptic connectivity between the piriform cortex (PC)
and its ascending and descending inputs from the olfactory bulb
(OB) and orbitofrontal cortex (OFC) following OD rule learning.
Here, using recordings of evoked field post-synaptic potentials in
behaving animals, we examined the dynamics by which synaptic
connectivity from the OB and OFC to the PC are modified
during rule acquisition. We show profound differences in the
dynamics and strength of synaptic connectivity modulation
between the ascending and descending inputs. During rule
learning acquisition, the ascending synaptic connectivity from
the OB to the anterior and posterior PC is simultaneously
enhanced. Notably, the daily OB electrical stimulation used to
examine the strength of synaptic inputs enhanced the rate of rule
learning. In sharp contrast, the synaptic input in the descending
pathway from the OFC was significantly reduced during rule
learning acquisition. OFC stimulation had no effect on the rate at
which the rule was acquired. Once rule learning was established,
the strength of synaptic connectivity in the two pathways
resumed its pre-training values. We suggest that acquisition
of olfactory rule learning requires a transient enhancement of
ascending inputs to the PC, synchronized with a parallel decrease
in the descending inputs. This combined short-lived modulation
is required to enable the PC network to reorganize in a manner
that enables it to first acquire and then maintain the rule.
Human exposure to acrolein – time dependence on
TRPA1 agonists
Anna-Sara Claeson, Nina Lind
Department od Psychology, Umeå university Umeå, Sweden
The objective of the study was to examine the time dependence
on sensory irritation potency of acrolein (2-propenal) in humans.
Concentrations at or below earlier reported thresholds that
initially are too low to evoke sensory irritation in the eye but
might do so in exposures up to 60 minutes were used. Acrolein
is a known TRPA1 agonist present in cigarette smoke, smoke
from fires, automobile exhaust and smog. The TRPA1 channel
is activated by electrophilic compounds that form covalent
bonds with cysteine residues. Because of this mechanism
of activation one can expect duration of exposure to be of
importance in evoking sensory irritation. The exposures occurred
in an exposure chamber and the subjects were breathing fresh
air through a mask that covered the nose and mouth. All
participants took part in four exposure conditions, differing in
duration and concentration. The concentrations of acrolein
(diluted in heptane) were 0.35, 0.07, 0.05 and 0 ppm (during
15, 45, 60 and 30 min, respectively). During the 30 minutes of
exposure subjects were exposed to only heptane at the same
concentration as in the other exposures (4.9 ppm). During
exposure, eye irritation was rated on Borg’s CR-100 scale.
Human exposure to acrolein at sub-threshold concentrations
showed a cumulative effect on sensory irritation. During
exposure to 0.35 ppm (but not 0.07 and 0.05 ppm) acrolein
evoked a significant increase in irritation compared to the control
condition after about 12 minutes of exposure. During exposure
to 0.07 and 0.05 ppm only some of the subjects reported
increased irritation after about 30 minutes of exposure. A large
variability in reported sensory irritation was seen between
individuals and this may be due to individual differences in the
ability to remove the electrophilic irritants from the cornea.
Acknowledgements: The Swedish Research Council FORMAS
#P115 POSTER SESSION III:
TRIGEMINAL; HUMAN OLFACTORY
PSYCHOPHYSICS; TASTE PERIPHERY
Solitary Chemosensory Cells in Human Nasal Epithelium
Sarah E Cooper 1 , Marco Tizzano 2 , Vijay R Ramakrishnan 1 ,
Henry P Barham 1 , Jameson K Mattingly 1 , Thomas E Finger 1,2 ,
Sue C Kinnamon 1,2
1
University of Colorado, Department of Otolaryngology Aurora, CO,
USA, 2 University of Colorado, Department of Cell and Developmental
Biology Aurora, CO, USA
POSTER PRESENTATIONS
Solitary chemosensory cells (SCCs) described in rodents rely on
the bitter taste transduction cascade to detect potential irritants
within the airways. SCCs express all of the taste GPCR signaling
effectors including T2R bitter taste receptors, a-gustducin,
PLCb2, and the transduction channel TRPM5. SCCs are
Abstracts are printed as submitted by the author(s).
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