title: Background Signal as an in Situ Predictor of Dopamine Oxidation Potential: Improving Interpretation of Fast-Scan Cyclic Voltammetry Data.
abstract: Background-subtracted fast-scan cyclic voltammetry (FSCV) has emerged as a powerful analytical technique for monitoring subsecond molecular fluctuations in live brain tissue. Despite increasing utilization of FSCV, efforts to improve the accuracy of quantification have been limited due to the complexity of the technique and the dynamic recording environment. It is clear that variable electrode performance renders calibration necessary for accurate quantification; however, the nature of in vivo measurements can make conventional postcalibration difficult, or even impossible. Analyte-specific voltammograms and scaling factors that are critical for quantification can shift or fluctuate in vivo. This is largely due to impedance changes, and the effects of impedance on these measurements have not been characterized. We have previously reported that the background current can be used to predict electrode-specific scaling factors in situ. In this work, we employ model circuits to investigate the impact of impedance on FSCV measurements. Additionally, we take another step toward in situ electrode calibration by using the oxidation potential of quinones on the electrode surface to accurately predict the oxidation potential for dopamine at any point in an electrochemical experiment, as both are dependent on impedance. The model, validated both in adrenal slice and live brain tissue, enables information encoded in the shape of the background voltammogram to determine electrochemical parameters that are critical for accurate quantification. This improves data interpretation and provides a significant next step toward more automated methods for in vivo data analysis.
authors.affiliation: Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States.
authors.forename: Carl J
authors.initials: CJ
authors.lastname: Meunier
authors.affiliation: Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States.
authors.forename: James G
authors.initials: JG
authors.lastname: Roberts
authors.affiliation: Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States.
authors.forename: Gregory S
authors.initials: GS
authors.lastname: McCarty
authors.affiliation: Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States.
authors.forename: Leslie A
authors.identifier: 0000-0002-0978-9795
authors.initials: LA
authors.lastname: Sombers
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D014150:Antipsychotic Agents / Q000494:pharmacology; D001703:Biophysics; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D004558:Electric Stimulation; D055664:Electrochemical Techniques; D004566:Electrodes; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008297:Male; D009434:Neural Pathways / Q000187:drug effects / Q000378:metabolism; D010084:Oxidation-Reduction; D051381:Rats; D017207:Rats, Sprague-Dawley; D012110:Reserpine / Q000494:pharmacology; D019805:alpha-Methyltyrosine / Q000494:pharmacology
chemical_list: D014150:Antipsychotic Agents; D004791:Enzyme Inhibitors; D019805:alpha-Methyltyrosine; D012110:Reserpine; D004298:Dopamine
keywords: Carbon-fiber microelectrode; calibration; electrochemical impedance spectroscopy; electrochemistry; in vivo