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Poster Full Abstracts - Neurophysiology and Behavior
Poster board number is above title. The first author is the presenter
298
manifesting as a longer lived fly. Conversely, the loss of inhibitory transmitters should lead to an excess of AKH release and a shorter lived fly during
starvation. We identified the receptor for the proctolin, octopamine, allatostatin c (ASTc), and pyrokinin as candidate molecules that participate in regulation
of AKH signaling. We further validated these findings, by employing single cell PCR and found specific expression of these genes in AKH cells. To directly
assess hormonal impact on AKH cell activation we employed GCaMP imaging. ASTc addition increased AKH cell excitability; this response was, in part,
dependent on AMPK. The significance of this finding might suggest an additional target of AMPK modulation and we speculate that this may be a
conserved feature of metabolic homeostasis.
624C
The Role of Hormones in the Stress Response.
Kathryn J. Argue, Wendi S. Neckameyer. Pharmacological and Physiological Sciences, Saint Louis
University School of Medicine, St. Louis, MO.
We have predicted that through complex neuroendocrine interactions, gonadotropic hormones will modulate the recruitment of neurons into the stress
response circuitry and therefore alter behavioral parameters. We assayed both heart rate and locomotion, since these have been shown to be altered in
response to stress, and are modulated, at least in part, by dopamine (DA). In flies, juvenile hormone (JH) is one of the major gonadotropic hormones shown
to be important for reproductive competence and mature sexual signaling. We have data showing that JH interacts directly with DA in vivo and that
manipulation of the levels of JH can have long-term effects on the animals’ behavior. Ecdysone is another important gonadotropic hormone in Drosophila; it
is the only steroid hormone in flies and has been shown to be important for generation and growth of adult-specific DA circuits (Mesce, 2002). Using
pharmacological and transgenic manipulations to investigate the role of both JH and ecdysone in modulation of the stress response in Drosophila, we have
demonstrated that the actions of these hormones on the stress response circuitry are both temporally and sexually dimorphic. This work has been funded by
NIMH 1RO1MN083771 and NSF 0616062.
625A
The membrane-bound ecdysteroid receptor DopEcR plays a unique role in the regulation of behavioral response to ethanol in Drosophila.
Emily
Petruccelli, Toshihiro Kitamoto. 51 Newton Rd, University of Iowa, Iowa City, IA.
Steroid hormones are critical modulators of various biological processes across phyla. Although actions of steroids are primarily mediated by nuclear
hormone receptors, some steroid responses cannot be explained by this classical “genomic” mechanism because they occur rapidly and independent of
mRNA synthesis. Despite the potential importance of such “non-genomic” steroid actions, their physiological functions and underlying mechanisms are still
poorly understood. Drosophila DopEcR is a G-protein coupled receptor that has been implicated in non-genomic actions of ecdysteroids (ecdysteroid and
20-hydroxyecdysone), the major steroid hormones in insects. In heterologous culture systems, DopEcR responds to both ecdysteroids and the catecholamine
dopamine to rapidly activate MAPK and cAMP signaling pathways, respectively (Srivastava et al., 2005). The role of DopEcR in vivo, however, still
remains largely elusive. We have recently identified a hypomorphic allele of Drosophila
DopEcR
(
DopEcR
PB1
) and found that
DopEcR
mutants are defective
in both associative and non-associative learning (Ishimoto et al., submitted). Here we further discover that
DopEcR
mutants show various aberrant behaviors
in response to ethanol. First,
DopEcR
PB1
flies are more sensitive to the effect of ethanol on postural control, similar to amnesiac mutants. Second, as seen in
flies with enhanced EGFR signaling,
DopEcR
PB1
flies display increased resistance to ethanol-induced sedation. Third, resistance to ethanol-induced sedation
is drastically enhanced in
DopEcR
PB1
mutant males, but not females, following heat shock. Our results suggest the DopEcR can be used to study the in vivo
functions and molecular mechanisms for non-genomic actions of steroids while also offering important insights into the molecular and cellular
underpinnings of behavioral response to alcohol. Srivastava et al. (2005) J Neurosci 25, 6145-6155.
626B
A genetic RNAi screen for G-protein coupled receptors regulating
Drosophila
flight.
Tarjani Agrawal, Gaiti Hasan. Natinal Centre for Biological
Sciences, TIFR, Bangalore, INDIA.
IP
3
is a second messenger that activates IP
3
receptor and leads to release of calcium from endoplasmic reticulum to cytosol. Pan-neuronal down regulation
of the IP
3
receptor in
Drosophila
results in wing posture and flight physiology defects
(1)
. Binding of ligands to G-protein coupled receptors (GPCRs) can
lead to IP
3
formation in the cytosol. I am interested in identifying the neuronal GPCRs which function through IP
3
mediated calcium release and regulate
flight in
Drosophila
.
In order to down-regulate the expression of GPCRs in neurons, a tissue specific expression technique of UAS-GAL4 was used. RNAi strains to all the
predicted GPCRs in
Drosophila
genome are available at the Vienna Drosophila RNAi Centre. Flight phenotype by pan neuronal down regulation of all
GPCRs was checked. Flight assays were done by recording single flight movies or by measuring firing activity from the dorsal longitudinal muscles, for 30
sec after giving an air puff.
I have screened 110 non-gustatory and non-olfactory GPCRs present in the
Drosophila
genome. This helped me to identify 20 receptors which affect
flight. Most of these receptors are activated by neuropeptides or neurotransmitters. Down regulation by RNAi expression for 7 GPCRs resulted in
phenotypes other than flight. These receptors were tested in sub-neuronal domains for flight defects. To investigate if these receptors function through IP
3
mediated calcium release, a modifier screen using an activated form of the G-protein (Ac-Gq) or over-expression of an intracellular calcium signalling
molecule (dSTIM) is in progress. I have identified a putative neuropeptide receptor that appears to regulate flight through IP
3
mediated calcium release in
glutamatergic neurons. Identification of receptors that regulate complex motor behaviors like flight will help understand neuromodulation of rhythmic motor
behaviors.
References:
1. Agrawal,et al.(2010), J Neurosci 30, 1301-1313.
627C
Characterization of three ligand gated ion channel subunits - Potential pesticide targets?
Daniel Feingold, Stephanie Bourque, Patrick Janukavicius,
Saima Sidik, Laura Nilson, Joseph Dent. Biol, McGill Univ, Montreal, QC, Canada.
Cys-loop ligand gated ion channels (LGICs) are pentameric neurotransmitter receptors that are ubiquitous in both vertebrate and invertebrate nervous
systems. Their large diversity as well as their central role in mediating rapid synaptic transmission has made these channels attractive molecular targets for