Presentation Type

Poster

Faculty Mentor’s Full Name

Sarah Certel

Faculty Mentor’s Department

Biological Sciences

Abstract

Out -of-context aggression is being recognized more in disease and injury states. In the Certel Lab, we are using Drosophila melanogaster as a model organism to understand the cellular mechanisms that regulate aggression, and we are particularly interested in the roles of neuromodulators, such as monoamines, in regulating aggression. Monoamines are released at synaptic sites via synaptic vesicles, but they are also released at extrasynaptic sites, such as the cell body, via large dense-core vesicles (LDCVs). In Drosophila, the monoamine octopamine (OA) is similar in structure and function to norepinephrine, and it is required for male aggression. In the current study, the relevance of OA release at the synapse in promoting Drosophila male aggression was tested, with the hypothesis that shifting release of OA away from the synapse to release on a widespread, global scale would impact aggression. To achieve this shift, OA was primarily released from LDCVs instead of synaptic vesicles, and this was accomplished through expression of a mutant Drosophila vesicular monoamine transporter (dVMAT), which involved a substitution of tyrosine 600 of dVMAT for alanine (Y600A dVMAT). Y600A dVMAT was expressed in OA neurons using the GAL4/UAS system, and aggressive behaviors measured were lunges and wing threats. Latency to lunge, which at large values can indicate decreased aggression, was also measured. Courtship, measured as a wing extension coupled to a secondary courting behavior, was also scored. No significant differences in courtship were observed between control and experimental flies, but compared to controls, experimental flies exhibited significant decreases in all of the measured aggressive behaviors. Also, latency to lunge was significantly increased in experimental flies. These results demonstrate that synaptic release of OA is required for male aggression, but synaptic release of OA from OA neurons is not required for courtship behaviors, suggesting important functional considerations for OA release sites.

Category

Life Sciences

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Apr 17th, 3:00 PM Apr 17th, 4:00 PM

Behavioral Impacts of Octopamine Release on a Global vs. Local Scale

UC South Ballroom

Out -of-context aggression is being recognized more in disease and injury states. In the Certel Lab, we are using Drosophila melanogaster as a model organism to understand the cellular mechanisms that regulate aggression, and we are particularly interested in the roles of neuromodulators, such as monoamines, in regulating aggression. Monoamines are released at synaptic sites via synaptic vesicles, but they are also released at extrasynaptic sites, such as the cell body, via large dense-core vesicles (LDCVs). In Drosophila, the monoamine octopamine (OA) is similar in structure and function to norepinephrine, and it is required for male aggression. In the current study, the relevance of OA release at the synapse in promoting Drosophila male aggression was tested, with the hypothesis that shifting release of OA away from the synapse to release on a widespread, global scale would impact aggression. To achieve this shift, OA was primarily released from LDCVs instead of synaptic vesicles, and this was accomplished through expression of a mutant Drosophila vesicular monoamine transporter (dVMAT), which involved a substitution of tyrosine 600 of dVMAT for alanine (Y600A dVMAT). Y600A dVMAT was expressed in OA neurons using the GAL4/UAS system, and aggressive behaviors measured were lunges and wing threats. Latency to lunge, which at large values can indicate decreased aggression, was also measured. Courtship, measured as a wing extension coupled to a secondary courting behavior, was also scored. No significant differences in courtship were observed between control and experimental flies, but compared to controls, experimental flies exhibited significant decreases in all of the measured aggressive behaviors. Also, latency to lunge was significantly increased in experimental flies. These results demonstrate that synaptic release of OA is required for male aggression, but synaptic release of OA from OA neurons is not required for courtship behaviors, suggesting important functional considerations for OA release sites.