Givaudan-Roure Lecture - Association for Chemoreception Sciences

37 Poster [ ] Vomeronasal Organ
EXPRESSION PATTERN OF GENES FOR NOTCH
SIGNALING PATHWAY IN MOUSE VOMERONASAL ORGAN
DURING ONTOGENY AND REGENERATION AFTER
REMOVAL OF ACCESSORY OLFACTORY BULB.
Wakabayashi Y. 1, Ichikawa M. 2 1Research Fellow of the Japan Society
for the Promotion of Science, Tokyo, Japan; 2Dep Basic Tech and
Facilities, Tokyo Metropol Inst Neurosci, Tokyo, Japan
Vomeronasal receptor neurons (VRNs) proliferate and differentiate
continuously throughout life. Proliferation of VRNs mainly occurs in
the marginal region of the sensory epithelium of adult vomeronasal
organ (VNO). The Notch signaling pathway is involved in cell fate
decisions and differentiation during developmental CNS. We have
studied whether Notch signaling pathway involves in differentiation
and proliferation of VRNs during ontogeny and regeneration.
In this study, we examined the expression patterns of Notch and
their ligands, Delta and Jagged, using in situ hybridization during
ontogeny and regeneration after removal of accessory olfactory bulb
(AOBX) in mice. In adult VNO, a few Notch1(+), Delta1(+) and
BrdU(+) cells appeared only in the marginal region, whereas Jagged2
was expressed in all VRNs. Notch1(+), Delta1(+) and BrdU(+) cells
located close to the basal lamia at embryonic days 14.5 and 16.5,
whereas expression level of Jagged2 was very low in comparison with
adult. At AOBX day2, number and location of Notch1(+), Delta1(+)
and BrdU(+) cells did not change. Expression pattern of Jagged2 did
not change. At AOBX day7, large amount of Notch1(+), Delta1(+) and
BrdU(+) cells appeared in the marginal region, whereas expression
pattern of Jagged2 did not change. These results suggested that the
interaction of Notch1(+) and Delta1(+) cells play important roles in
vomeronasal neurogenesis of VNO during ontogeny as well as
regeneration after AOBX mice.
38 Poster [ ] Vomeronasal Organ
THE ROLE OF THE VOMERONASAL SYSTEM IN FOOD
PREFERENCES OF THE GRAY SHORT-TAILED OPOSSUM,
MONODELPHIS DOMESTICA
Daniels Y. 1, Halpern M. 2, Zuri I. 1 1Anatomy and Cell Biology,
Downstate Medical Center, Brooklyn, NY; 2Anatomy & Cell Biology,
Downstate Medical Center, Brooklyn, NY
The vomeronasal system (VNS) is usually considered primarily a
pheromone-detecting system. In snakes and lizards, this system is also
important for feeding behavior. To date, no studies have reported
feeding deficits in mammals deprived of a functional VNS. M.
domestica is considered a primitive mammalian species that was
recently introduced into laboratories. Since these opossums respond to a
variety of foods, they are a good model to investigate the role of the
VNS in food preferences in mammals.
The six male and seven female gray short-tailed opossums used in
this study were simultaneously presented with four foods, one from
each of the following food groups: fruits (apples, oranges, peaches,
cantaloupes), meats (mealworms, chicken, pork, crickets), processed
vegetables (raisin bran, cheerios, whole wheat bread, bagel) and
unprocessed vegetables (corn, peppers, carrots, broccoli). Before
blocking access to the vomeronasal organ (VNO) with gel foam and
Crazy Glue, the opossums selected meats most frequently and fruits
more frequently than processed and unprocessed vegetables. Following
VNO blockage, the opossums demonstrated no preference between the
different food groups. This study suggests that without a functional
vomeronasal organ, the food preferences of gray short-tailed opossums
are significantly impaired.
Supported by NIDCD Grant # DC02745.
10
39 Slide [ ] Vomeronasal Organ
CHEMO-INVESTIGATORY BEHAVIOUR OF MALE MICE IN
DETECTING ESTRUS: ROLE OF OLFACTORY-
VOMERONASAL SYSTEM
Raman S.A. 1 1Animal Scinece, Bharathidasan University,
Trichirappalli, India
S.ACHIRAMAN AND G.ARCHUNAN
Department of Animal Science, Bharathidasan University
Tiruchirappalli-620 024, Tamilnadu.
INDIA
achiraman_s@yahoo.co.in
The aim of the present study is to evaluate whether the male
mouse is capable of discriminating the female urinary odour of different
reproductive phases (with a view to detect estrus using Y-maze
apparatus and to establish the relationship of olfactory - vomeronasal
system and chemo-investigatory behaviour in estrus detection. Hence,
normal, vomeronasal organ (VNO)-ablated and Zinc Sulphate-irrigated
mouse were used as test animals. Various behaviours such as frequency
of visit, duration of visit, sniffing, licking, body rubbing and grooming
were recorded. The normal mice frequently visited and devoted more
time in delivering various behaviours towards the estrus urine sample in
comparison to that of non-estrus urine. The VNO-ablated mice showed
significant reduction in response to estrus urine (duration of visit and
self-grooming) than that of ZnSO4-irrigated mice. However, the
ZnSO4-irrigated mice showed significant reduction in frequency of
visits to the urine samples. These results clearly reveal that the VNO
play a significant role in the detection of estrus in mice. The present
results also suggest that male mice preferentially communicate sexual
interest via self-grooming towards the opposite sex. By self-grooming
at higher rates, male mice may be broadcasting scents to attract
potential mates or to inform their willingness to mate.
40 Poster [ ] Vomeronasal Organ
NEUROGENESIS, MIGRATION AND APOPTOSIS IN THE
VOMERONASAL EPITHELIUM OF ADULT MICE
Martinez-Marcos A. 1, Quan W. 2, Jia C. 2, Halpern M. 3 1Departamento
de Ciencias Medicas, Universidad de Castilla-La Mancha, Albacete,
Albacete, Spain; 2Anatomy and Cell Biology, Downstate Medical
Center, Brooklyn, NY; 3Anatomy & Cell Biology, Downstate Medical
Center, Brooklyn, NY
Neurogenesis in the adult mouse vomeronasal organ appears to occur
in the central regions, but is more prevalent at the edges of sensory
epithelium. Basal cells at the center of the epithelium participate in cell
replacement. It is unknown whether dividing cells at the edges
constitute a reservoir for growth, become apoptotic or participate in
neural turnover. This latter possibility implies a process of horizontal
migration. The present work addresses this controversy by injecting
bromodeoxyuridine in adult mice and allowing them to survive for
various intervals. The vertical and horizontal position of labeled cells
was analyzed as a function of time. Both, vertical and horizontal
migration of labeled cells were detected. Cells at the center of the
epithelium migrate vertically to become neurons as demonstrated by coexpression
of olfactory marker protein. Cells at the edges migrate
horizontally toward the center. After 42 days, however, they have
migrated less than 10% of the distance from the edge (0%) to the center
of the epithelium (100%), thus making it likely that if these cells
participate in neural turnover it is only in marginal regions. The pattern
of distribution of apoptotic cells has been studied and, interestingly, it is
similar to that of dividing cells. These results support the idea that
sensory cell renewal in the mouse vomeronasal organ occurs through a
process of vertical migration. Supported by grant DC02745.