Basic HTML Version
#P227
POSTER SESSION VI:
OLFACTION CNS; TASTE PERIPHERY &
CNS; MULTIMODAL RECEPTION
Connexins and AMPA receptor subunits have diurnal rhythms
of expression in the rat olfactory bulb
John T Corthell, DA Fadool, Paul Q Trombley
FSU, Biological Science Tallahassee, FL, USA
Connexins and AMPA receptors together allow mitral and tufted
cells in the mammalian olfactory bulb to fire synchronous action
potentials and thus affect synaptic transmission and odor
processing. We examined connexins 36, 43, and 45 within the
rat olfactory bulb for rhythms in expression. We found, via
quantitative PCR, that connexin36 and connexin45 mRNAs are
expressed with a specific diurnal rhythm. Because the
synchronicity of firing is an effect of both connexin36 and AMPA
receptors, we examined the AMPA receptor subunits GluR1-4 via
qPCR as well. mRNA for GluR1 and GluR2 appeared to peak in
the dark phase and decrease in the light. We also examined the
proteins for these genes in the plasma membrane, using Western
analysis and subcellular fractionation to isolate the membranes.
We found that connexins 43 and 45 expressed peaks in the dark
phase, as did GluR1 and GluR3 proteins. Some protein expression
in the membrane peaked during the light phase, which may indicate
the presence of an oscillatory input to the olfactory bulb aside from
the endogenous oscillations first identified by Granados-Fuentes
et al. (2004).
#P228
POSTER SESSION VI:
OLFACTION CNS; TASTE PERIPHERY &
CNS; MULTIMODAL RECEPTION
A quantitative analysis of the Islands of Calleja in the
Olfactory Tubercle
Stacey Adjei, Daniel W. Wesson
Case Western Reserve University, Neurosciences
Cleveland, OH, USA
The olfactory tubercle (OT) is an olfactory cortical structure with
an exceptionally unique cytoarchitecture. One of the unique
features of the OT is the presence of dense cell clusters termed
‘islands of Calleja’ (IC) within the multiform cell layer (layer iii).
The apparent predominant localization of the ICs within the OT
suggests a role for the ICs in olfactory processing or perhaps more
specifically odor-guided behaviors, however, the function of the
ICs remain unknown. Precluding this realization, not even a
thorough quantification of the ICs anatomical properties is
currently available. To address this, here we examined the ICs from
20µm cresyl violet stained sections of 25 male C57bl/6J mice.
Following staining, basal forebrain sections were sequentially
imaged to allow reconstruction and quantification of the ICs. We
found evidence for hemispheric differences in the numbers of ICs
of individual mice. We also observed that the volume of the ICs,
but not cellular density, is heterogeneous within individual mice,
yet in manners not necessarily predicted by anterior-posterior or
medial-lateral positioning in the OT. More ICs are found within
posterior versus anterior portions of the OT. Interestingly, the major
IC as well as some other ICs were often found to be donut shaped
in nature, with a void in their center, verses simply crescent or
spherical shaped as previously thought (Fallon et all., J Comp
Neurol, 1978). Studies to explore how these factors change
throughout aging in mice are underway. These neuroanatomical
studies provide a foundation for future works exploring the
physiological contributions of the ICs in the context of olfactory
perception and odor-guided behaviors. Acknowledgements:
Supported by NSF grant ISO-1121471 to D.W.W.
#P229
POSTER SESSION VI:
OLFACTION CNS; TASTE PERIPHERY &
CNS; MULTIMODAL RECEPTION
Differential projections of the anterior and posterior
medial amygdala in female mice
Brett T. DiBenedictis
1
, Michael J. Baum
1
, James A. Cherry
2
1
Boston University Biology Department Boston, MA, USA,
2
Boston University Psychology Department Boston, MA, USA
In rodents both appetitive and consumatory behaviors concerned
with reproduction are mediated by chemosignals released from
opposite sex conspecifics. These signals are detected by two
anatomically distinct systems, the main olfactory system (MOS)
and the accessory olfactory system (AOS), which detect primarily
volatile and non-volatile body odor cues, respectively. Recently, it
has been shown that the medial amydgala (Me) receives inputs
from both the main and accessory olfactory systems, with inputs
from the MOS to the Me being selectively activated by opposite
sex urinary odors (Kang et al., 2009). It has been suggested anterior
(MeA) and posterior (MeP) Me subdivisions play distinct roles in
the processing of body chemosignals (DiBenedictis et al., 2012;
Maras & Petrulis, 2006). It is likely that differential processing of
olfactory information by Me subnuclei reflects differences in their
downstream targets. To test this hypothesis, we injected female
mice with the anterograde dextran amine, Fluoro-Ruby into either
the MeA or MeP and quantified resultant labeled fiber densities in 8
forebrain projection target sites. We found significantly denser
anterograde fiber labeling of the posterolateral cortical amygdala
(PLCo), bed nucleus of the stria terminalis (BNST) and shell of the
nucleus accumbens (AcbSh) in MeP-injected females compared to
MeA-injected females, whereas we found equivalent innervation of
the mOT, AcbC, MPA, VMHdm and VMHvl. Several sites
preferentially targeted by the MeP are associated with the
mesolimbic reward system, corroborating previous behavioral data
from our laboratory suggesting that a functional MeP is necessary
for the normal display of motivational aspects of sexual behavior,
including the intrinsic preference of females to investigate male
urinary odors. Acknowledgements: NIH grant R01DC008962
#P230
POSTER SESSION VI:
OLFACTION CNS; TASTE PERIPHERY &
CNS; MULTIMODAL RECEPTION
Parallel odor processing by two anatomically distinct olfactory
bulb target structures
Colleen A. Payton
1
, Donald A. Wilson
2
, Daniel W. Wesson
1,2
1
Case Western Reserve Univ, Neurosciences Cleveland, OH,
USA,
2
NYU School of Med & Nathan Kline Institute
Orangeburg, NY, USA
The olfactory cortex encompasses several anatomically distinct
regions each hypothesized to provide differential representation and
processing of specific odors. Studies exploring whether or not the
diversity of olfactory bulb input to olfactory cortices has functional
meaning, however, are lacking. Here we tested whether two
anatomically major olfactory cortical structures, the olfactory
tubercle (OT) and piriform cortex (PCX), differ in their neural
representation and processing dynamics of odors by performing
in
Abstracts | 103
Abstracts are printed as submitted by the author(s)
P O S T E R P R E S E N T AT I O N S