Detection and Quantification of Neurotransmitters in Drosophila melanogaster by Capillary Electrophoresis- Fast Scan Cyclic Voltammetry

In this work, the development and use of capillary electrophoresis coupled to fast-scan cyclic voltammetry (CE-FSCV) for the separation, detection, and quantification of neurotransmitters and their metabolites in Drosophila melanogaster tissues is discussed. In Chapter 1, the background material for this thesis: neurotransmitters, Drosophila as a model organism, separations of neurotransmitters, capillary electrophoresis, electrochemical detection, and past applications of CE-FSCV are explained. In Chapter 2, the application of CE-FSCV to the determination of tyramine, serotonin, octopamine, and dopamine in the central nervous system (CNS) of the larva, pupa, and adult Drosophila is discussed. Sex specific differences in neurotransmitter tissue content of the adult brain are also discussed. In Chapter 3, a new CE-FSCV method for the detection of histamine, the neurotransmitter required for vision in Drosophila, and its metabolite carcinine in a variety of Drosophila tissues is developed. Histamine and carcinine have not previously been analyzed by CE-FSCV, and this method allows direct detection of both of these analytes. Additionally, the detection and quantification of a metabolite of dopamine, N-β-alanyl dopamine, is possible using this method. Histamine, carcinine, dopamine, and N-β-alanyl dopamine content in a wild type strain along with two metabolic mutants is determined. This method provides the foundation for Chapter 4, where the tissue content of histamine and carcinine is determined in adult brains, larval central nervous systems, and adult eyes from visual mutants. Lastly, I have laid out future directions for the use of CE-FSCV and other methods to further understand the tissue content distribution of neurotransmission.