Abstracts - Association for Chemoreception Sciences

P O S T E R S
connexin proteins. The OB also exhibits circadian rhythms of
both electrical activity and odor sensitivity, but the cellular
mechanisms underlying these rhythms are unknown. Many
circadian rhythms are under the influence of the daily rhythm of
melatonin released by the pineal gland. Recent data suggest that
melatonin regulates the expression of connexin 43 in myometrial
cells and this contributes to synchronous rhythmic contractions
of the uterus during childbirth. Collectively, these data led to the
hypothesis that melatonin may contribute to the circadian activity
of the OB by regulating gap junction expression and enhancing
synchronous activity. To test this hypothesis, neonatal OB cells,
grown in primary culture, were treated with 3 nM melatonin and
connexin expression was examined by immunofluorescence.
Connexin 43, in control tissue, was expressed primarily at the
borders of contact between astrocytes. In contrast, melatonintreated
astrocytes displayed increased connexin 43 expression,
which included a diffuse cellular expression pattern in addition to
expression at cell-to-cell borders. These results suggest that
melatonin may contribute to the circadian activity of the OB by
enhancing electrical coupling via increased gap junction
expression. Molecular analyses of these effects, and the effects of
melatonin on connexins 36 and 45, are also being examined.
Acknowledgements: Supported in part by the FSU Department of
Biological Science and Program in Neuroscience
#P40 POSTER SESSION I: TASTE IMAGING &
PSYCHOPHYSICS; CENTRAL TASTE;
MULTIPLE MODALITIES; CENTRAL &
PERIPHERAL OLFACTION
Odors eliciting Fear: a Conditioning Approach to Idiopathic
Environmental Intolerance
Patricia Bulsing 1 , Arne Leer 2 , Monique A Smeets 2 ,
Marcel van den Hout 2
1
Unilever Vlaardingen, Netherlands, 2 Utrecht University Utrecht,
Netherlands
Individuals with Idiopathic Environmental Intolerance (IEI) seem
to fear odorous chemicals. To determine whether IEI can be
conceived of as an “odor phobia”, we tested whether odors can
elicit stress responses (1); and whether odors, after association
with fear compared to before, are evaluated as less pleasant
(2) and avoided more (3). Method: Using differential classical
conditioning paradigm, an odor (either rotten egg as CS+
[CS: Conditioned Stimulus] and peach as CS-, or vice versa), were
conditioned to an electrical shock as Unconditioned Stimulus
(US). The acquisition phase consisted of 6 presentations of the
CS+ followed by electrical shock and 6 presentations of the CSalone.
The extinction phase consisted of 6 CS+ and 6 CS- trials,
with no US. Stress response was assessed via Skin Conductance
Response (SCR); pleasantness via rating scales; avoidance via
sniffing. Results: SCR increased significantly to both odors, but
stress to rotten egg did not extinguish (1); a significant (p =.03)
change in pleasantness during acquisition was encountered, with
the CS+ being liked less after conditioning (2); sniffing volume
associated with the CS+ decreased immediately after the first
trial(s), but reduction in volume was not significant over 6 trials
(3). Discussion: The finding that odors can be conditioned to
stress responses, leading to reduced liking for these odors, support
a fear conditioning conception of IEI. However, the absence of
extinction and avoidance of the CS+ are problematic in the light
of the theory and additional research is needed, especially since
extinction would be the treatment of choice in view of the theory.
Acknowledgements: NWO Vidi 452-03-334
#P41 POSTER SESSION I: TASTE IMAGING &
PSYCHOPHYSICS; CENTRAL TASTE;
MULTIPLE MODALITIES; CENTRAL &
PERIPHERAL OLFACTION
Species specific regulation of the olfactory bulb
dopaminergic phenotype
Kasturi Banerjee 1 , Shivraj Bhosle 1 , Harriet Baker 1,2 ,
John W. Cave 1,2
1
Burke Medical Research Institute White Plains, NY, USA,
2
Weill Cornell Medical College New York, NY, USA
Our previous studies indicated that the transcription factor ER81
regulates tyrosine hydroxylase (TH) expression in the mouse
olfactory bulb (OB) by directly binding to the TH proximal
promoter. A recent study suggested ER81 also regulates
expression of other genes necessary for the dopaminergic
phenotype by a molecular mechanism similar to TH, and this
ER81-dependent differentiation of the dopaminergic neuronal
phenotype is conserved from nematodes to mammals. However, a
phylogenetic analysis of genomic DNA sequences corresponding
to promoter regions for several dopaminergic genes in mammals
revealed that the reported binding sites that mediate ER81
regulation of the dopaminergic phenotype are not conserved.
Chromatin immunoprecipitation (ChIP) experiments with mouse
OB tissue suggested that ER81 binds to several proximal
promoter regions of many dopaminergic genes, but ChIP
experiments with OB tissue from dog indicate that orthologous
regions of these genes are not bound by ER81. Focusing on the
expression of TH, which is the rate-limiting enzyme in dopamine
biosynthesis, electromobility gel shift assays showed that
recombinantly expressed ER81 can bind the TH promoter from
rodents, but not humans. Transcription assays comparing human
and rat TH promoters in a cultured murine OB cell line also
suggested that there is species-specific regulation of TH. Together,
our findings suggest that there are species-specific molecular
mechanisms that regulate differentiation of OB dopaminergic
phenotype. However, these findings do not exclude the possibility
that there is also a conserved molecular differentiation pathway
that functions in combination with the species-specific
mechanisms. Acknowledgements: NIH DC008955
#P42 POSTER SESSION I: TASTE IMAGING &
PSYCHOPHYSICS; CENTRAL TASTE;
MULTIPLE MODALITIES; CENTRAL &
PERIPHERAL OLFACTION
The olfactory capabilities of mice with long-term unilateral
naris occlusion (UNO) and contralateral bulbectomy (bulb-x)
Cathy J Angely, David M Coppola
Department of Biology, Randolph Macon College Ashland, VA,
USA
UNO has been the most common method of effecting stimulus
deprivation in studies of olfactory plasticity. However, despite the
large corpus on the effects of this manipulation dating back to the
19th century, little is known about its behavioral sequela. Here we
report the results of classical olfactory habituation and
discrimination studies on adult mice that had undergone unilateral
bulb-x and contralateral naris occlusion perinatally. The olfactory
performance of UNO mice was compared to matched controls
that had unilateral bulb-x but intact nares. Both experiments
employed a masking protocol in which after successful
dishabituation or discrimination to pure odors (0.1% isoamyl
40 | AChemS Abstracts 2010 Abstracts are printed as submitted by the author(s)