Chemical Analysis of Neuropeptide Y and Glutamate using Carbon Fiber Microelectrodes and Fast-Scan Cyclic Voltammetry

Abstract ID 130292 Poster Board 538 Neuropeptide Y (NPY) plays a great role and importance on feeding, satiety, obesity, and weight. Due to its complicated peptide structure, measuring this chemical quickly and achieving high biocompatibility is difficult. Previous investigations have measured peptides by oxidizing amino acid residues like tyrosine using carbon fiber microelectrodes (CFMEs) and fast-scan cyclic voltammetry (FSCV). Here, we utilize the Modified Sawhorse Waveform (MSW) to identify Neuropeptide Y (NPY) by oxidizing tyrosine residues. The MSW enhances NPY measurement and sensitivity and selectivity by boosting efficient electron transfer kinetics compared to the triangle waveform used for dopamine detection. This method uses a holding potential of 1.2 V to achieve a limit of detection of 5 uM by etching and renewing the electrode surface, improving sensitivity and the ability to detect NPY and other monoamines simultaneously. When the MSW is applied onto CFMEs, it increases NPY selectivity over the triangle waveform, allowing for significant differentiation from other catecholamines including dopamine and serotonin. NPY was found to be adsorption controlled onto the surface of CFMEs. This sub-second and biocompatible measurement approach may improve the physiological measurement of NPY and reveal new insights. The successful identification of exogenously applied NPY in urine shows that this technology is suitable for biological studies and in vivo and ex vivo assessments. These findings demonstrate MSW's promise for quick subsecond and biocompatible NPY measurement and other larger neuropeptide assays. Through improved NPY quantification, we hope to better understand its physiological significance in vivo. Furthermore, we have also developed novel assays for the measurement of glutamate with CFMEs and FSCV. Glutamate is an important excitatory neurotransmitter and amino acid that serves as a biomarker for epilepsy and other neurological disorders. Currently, glutamate is not redox active at carbon electrode surface. We have utilized the enzyme Glutamate oxidase to modify CFMEs, which can metabolize glutamate to the redox active hydrogen peroxide. CFMEs were modified with glutamate oxidase to indirectly measure glutamate dynamics. These studies and future work will investigate the pharmacology of NPY and glutamate and will examine how certain drugs change extracellular levels of these molecules in real-time as potentially treatments for neurological disorders and states caused by the flux of these molecules.