Measurements of Dopamine in Drosophila using Fast-Scan Cyclic Voltammetry

Drosophila melanogaster, the fruit fly, is homologous to mammals in primitive neurobiology making it an advantageous model system in which to study the dynamics of dopamine regulation. However, there are few methods for measuring real-time release of dopamine in the intact fly nervous system because the size of the central nervous system (CNS) is so small. My dissertation research overcomes critical instrumentation barriers to develop the first real-time detection method for dopamine release in the fruit fly. Two methods using fast-scan cyclic voltammetry were developed to characterize dopamine homeostasis in an intact Drosophila CNS. In the first method, stimulated release was measured in Drosophila genetically modified to specifically express Channelrhodopsin2 (ChR2), a blue-light activated cation channel, in only dopaminergic neurons. In the second method, a micropipette back-filled with dopamine was implanted 15-20 µm away from a carbon-fiber microelectrode and clearance measured after dopamine was pressure ejected into the CNS. These novel methods open up the fly as a model system for studying basic mechanisms of neurotransmission.

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