XVI International Symposium on Olfaction and Taste - ecro

<strong>XVI</strong> <strong>International</strong> <strong>Symposium</strong> on Olfaction and Taste
Poster session II Poster #278
Chemosignal evaluation in the amygdala: Possible function of medial amygdala and medial-
caudal intercalated nucleus
Lindsey M Biggs 1 and Michael Meredith 1
1 Florida State University, Biological Sciences, Tallahassee, FL
lbiggs@neuro.fsu.edu
The vomeronasal organ is important for detection of conspecific and heterospecific chemosensory signals and relays
information to the medial amygdala via the accessory olfactory bulb. Anterior and posterior regions of the medial
amygdala (MeA, MeP) project to preoptic and hypothalamic areas involved in production of appropriate social behaviors.
Responses in the medial amygdala may represent an evaluation of chemosensory signals, categorizing stimuli based on
salience. In hamsters, immediate early gene FRAs expression increases in MeP as well as MeA after exposure to
conspecific chemosensory stimuli, while exposure to heterospecific stimuli increases FRAs expression only in MeP. The
medial-caudal intercalated nucleus (m-ICNc), a group of mostly GABAergic neurons lateral to MeP, may modulate MeP
activation, preventing a response to non-relevant stimuli. After exposure to heterospecific stimuli, FRAs expression in the
hamster m-ICNc is increased while MeP FRAs expression is suppressed and the inverse is true for responses to some
conspecific stimuli. Preliminary slice electrophysiology results suggest a functional connection between m-ICNc and
MeP and demonstrate that stimulation of m-ICNc leads to inhibition of MeP neurons. Intercalated cell clusters (ITC)
elsewhere in the amygdala have also been implicated in the modulation of activity in basolateral and central amygdala of
the fear conditioning circuit, via activation of dopamine D1 receptors located on GABAergic ITC neurons. Based on
these findings and the immediate early gene expression data it is possible that m-ICNc is involved in shaping MeP
response via dopamine D1 receptors on m-ICNc neurons. Ongoing slice electrophysiology experiments with bath-applied
drugs, including dopamine agonists and antagonists explore this hypothesis.
Supported by NIDCD grants R01-DC005813, T32-DC000044
Poster session I Poster #97
Identification of new semiochemicals for Spodoptera littoralis from host and non-host plants using
GC-SSR and GC-MS
Muhammad Binyameen 1 , Rickard Ignell 1 , Göoran Birgersson 1 , Bill S Hansson 2 and Fredrik Schlyter 3
1 Swedish University of Agricultural Sciences, Chemical Ecology, Plant Protection Biology, Alnarp, Sweden
2 Max Planck Inst for Chemical Ecology, Department of Evolutionary Neuroethology, Jena, Germany
3 Swedish University of Agricultural Sciences, Chemical Ecology, Plant Protection Biology, Alanrp, Sweden
muhammad.binyameen@slu.se
Spodoptera littoralis(Boisduval) (Lepidoptera: Noctuidae) is a polyphagous pest species on cotton ( Gossypium hirsutum)
and many other agricultural crops and vegetables. Plant volatiles are the predominant cues that drive the host-seeking
behaviour of S. littoralis female to select a host for feeding and/or oviposition. In a previous study, we used plant odors
that are behaviorally and/or electro-physiologically active for S. littoralis and other moth species to show that antennal
olfactory sensilla of female S. littoralis are innervated by different functional classes of olfactory sensory neurons
(OSNs). We also found that host leaves have some additional active ligands for OSNs that we did not have in our odor
panel tested. In the present study, we have, for the first time, conducted gas chromatography-coupled single sensillum
recordings (GC–SSR) on antennal olfactory sensilla of female S. littoralis in order to screen for additional putative host
attractants and non-host inhibitors. We used air-borne collections from undamaged and conspecific larvae damagedcotton
plants, as well as from flowers of lilac, Syringa vulgaris. GC–SSR recordings have so far revealed that a number
of OSN types strongly respond to many of the compounds in the biological extracts. The compounds have been
subsequently identified through gas chromatography coupled-mass spectrometry (GC–MS). Identification of
more bio-active compounds from non-host plants, Adhatoda vesica and Picea abies that we have shown to inhibit
female calling, mating and egg- laying, are in progress.
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