Mass Spectrometric Analysis of Neurologically-Relevant Molecules

The analysis and quantitation of neurologically-relevant molecules requires detection methods that are sensitive, selective, and applicable to a wide range of molecules. Targeted analysis using tandem mass spectrometry allows for the detection of molecules from complex matrices with an added level of selectivity. Mass spectrometry is on the leading edge of technological advances and improvements in our understanding of the intricate workings of the brain, allowing us to develop better models and better therapeutic approaches. In this thesis, I use tandem mass spectrometry to investigate two classes of neurochemicals: classical neurotransmitters, and potential therapeutic drugs based on endogenous neuropeptides. Chapter 1 will introduce existing sampling techniques and detection schemes for small molecule neurotransmitters and small peptides. We will also introduce two key concepts: insect models for understanding human neurotransmission, and the role of the blood-brain barrier in developing CNS-active pharmaceuticals. In Chapter 2 we develop a method to quantify small molecule neurotransmitters in tissue homogenate for the purpose of understanding how the bulk content of an insect brain can change under differing circumstances. Our approach allows for the analysis of a wider range of compounds with improved throughput compared to existing methods. Chapter 3 expands this method for the quantitation of five biogenic amines in Apis mellifera, to investigate the effect of infection by the microsporidian Nosema ceranae. Chapter 4 explores the role of glycosylation on the stability and blood-brain barrier permeability of peptide-based drugs. Chapter 5 expands this work to a series of Angiotensin 1-7 derivatives, for a study of the effect of different structural modifications to peptide-based drugs, with the goal of driving drug development toward more effective pharmaceuticals. Chapter 6 concludes this work and outlines the future directions of the research