Abstracts - Association for Chemoreception Sciences

#P222 POSTER SESSION V:
CENTRAL OLFACTION; CHEMOSENSORY
PSYCHOPHYSICS & CLINICAL STUDIES
In Vivo Expression of Osterix in Mouse Olfactory Bulb
Jung-Eun Kim 1 , Ji-Soo Park 2
1
Department of Molecular Medicine, Cell and Matrix Research
Institute, Kyungpook National University School of Medicine
Daegu, Korea, 2 Department of Molecular Medicine, Cell and
Matrix Research Institute, Kyungpook National University School
of Medicine Daegu, Korea
Osterix (Osx) is identified as an osteoblast-specific transcription
factor, which is required for skeletogenesis. Here, we examined
the expression of Osx in non-skeletal tissues. Together with high
expression in bones, Osx was moderately expressed in brain. Osx
expression in mouse brain was gradually increased during
postnatal developmental periods. Osx was highly expressed in
olfactory bulb rather than cerebral cortex and cerebellum. To
convince Osx expression in mouse olfactory bulb, Osx expression
was examined in brain of Osx heterozygous mice with a LacZ
knock-in in the Osx locus, resulting in strong X-gal staining in
mouse olfactory bulb. X-gal positive cells were located in mitral
and granule cell layer of olfactory bulb, confirming by
immunohistochemical analysis with anti-Osx antibody. Osxpositive
cells were specifically expressed in mature neuronal cells
as shown in merged images with NeuN. Morphological difference
was not observed in Osx heterozygous compared to wild-type
mice by cresyl violet staining. In immunofluorescence using
neuronal marker genes, the number, shape, and localization of
immature neurons, mature neurons, astrocytes, and proliferating
cells were identical in both wild-type and Osx heterozygous mice.
Even though there are no big differences in neuronal cells of Osx
heterozygotes compared to wild-type, the function of Osx in
olfactory bulb would be more studied. Consequently, in this
study, in vivo expression of Osx was first observed in mouse
olfactory bulb and this finding may provide a new function of
Osx in olfactory bulb not in only bone. Acknowledgements: NRF
2009-0071230, BK21 Project in 2010
#P223 POSTER SESSION V:
CENTRAL OLFACTION; CHEMOSENSORY
PSYCHOPHYSICS & CLINICAL STUDIES
Calbindin, Parvalbumin and Calretinin Immunoreactivity
in the Medial Amygdala of Male Hamsters
Lindsey M Silz, Michael Meredith
Florida State University Tallahassee, FL, USA
The hamster vomeronasal organ (VNO) detects chemosensory
signals from both conspecific and heterospecific species and has
strong direct projections via accessory olfactory bulb (AOB) to
anterior medial amygdala (MeA), which has strong projections to
MeP, thence to hypothalamic regions implicated in social
behaviors. VNO, AOB and MeA respond to natural conspecific
and heterospecific social signals, including flank gland secretion
(FGS) and vaginal fluid (HVF) from hamsters, and mouse urine
(MU). Subsets of these stimuli increase FRAs immediate early
gene (IEG) expression in MeP, suggesting selective responses to
biologically relevant stimulus categories. GABAergic inhibition
from intercalated nuclei (ICN) and interneurons within MeA/P
may determine the selective response in MeP. Calcium binding
proteins (CBPs), parvalbumin, calbindin, and calretinin, often
colocalize with GABA, and have been helpful in distinguishing
subgroups of GABAergic cells with different functions. A group
of large parvalbumin-ir cells extends from lateral MeA into the
anterior amygdaloid area. Calretinin-ir cell bodies and fibers are
densely concentrated in dorsal and ventral areas of MeA with few
fibers centrally. In MeP, large calretinin-ir cells are concentrated
dorsally. Calbindin-ir cells appear to be of two types, distributed
throughout MeA and MeP. ICN cells are not CBP-ir. We have
evidence for GABA suppression in MeP in response to
biologically relevant stimuli so we hypothesized that differences
in IEG activation of calcium binding protein-ir cells might reveal
details of the MeA/P circuits involved in categorical
chemosensory response. Preliminary double-label results suggest
that the ICN and calbindin-ir cells are differentially activated by
these stimuli, but that calretinin-ir and parvalbumin-ir cells are
not. Acknowledgements: Supported by DIDCD grant DC005813
#P224 POSTER SESSION V:
CENTRAL OLFACTION; CHEMOSENSORY
PSYCHOPHYSICS & CLINICAL STUDIES
Sexually Relevant Olfactory Stimuli Activate the Medial
Preoptic Nucleus in an Age-Dependent Manner
Daniel J Tobiansky 1 , Juan M Dominguez 1,2
1
Department of Psychology, The University of Texas at Austin
Austin, TX, USA, 2 Institute for Neuroscience, The University of
Texas at Austin Austin, TX, USA
The olfactory system plays a significant role in mediating
appetitive and consummatory aspects of sexual behavior in
rodents. Chemosensory input from the olfactory bulb and
vomeronasal organ project to the medial amygdala. This
information is then relayed, directly and indirectly, via the bed
nucleus of the stria terminalis to the medial preoptic area
(MPOA). The MPOA is a central integrative region in the
regulation of male sexual behavior present in most studied species.
In this study, sexually experienced adult- (~ 1 year old) and
elderly- (~2.5 years old) male rats were exposed to a partially
sedated female in estrous in a neutral cage for 10 minutes. An
hour later they were sacrificed and their brain immuno-processed
for the presence of Fos, the protein byproduct of the immediate
early gene c-fos, used here as a measure of cellular activation in
the medial preoptic nucleus (MPN), a central nucleus in the
MPOA. Analyses revealed no significant difference in the length
of time each group spent investigating the female. Analyses did
reveal differences in the number of cells containing Fos between
the two groups. Specifically, the caudal portion of the MPN in the
elderly rats had a higher number of Fos-positive cells when
compared with adult rats. There were no differences between the
two groups in the rostral and central regions of their MPN.
Higher activation in elderly males suggests a compensatory
mechanism, whereby more cells must be recruited to elicit
equivalent sexual activity as in adult males.
P O S T E R S
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