Tonic and Phasic Amperometric Monitoring of Dopamine Using Microelectrode Arrays in Rat Striatum

Martin Lundblad,Peter Huettl,Greg A Gerhardt,David A Price,Jorge E Quintero,Jason J Burmeister,Francois Pomerleau,Nancy R Zahniser

doi:10.3390/app10186449

Martin Lundblad, Peter Huettl + Show 6 more

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https://doi.org/10.3390/app10186449

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Abstract

Here we report a novel microelectrode array recording approach to measure tonic (resting) and phasic release of dopamine (DA) in DA-rich areas such as the rat striatum and nucleus accumbens. The resulting method is tested in intact central nervous system (CNS) and in animals with extensive loss of the DA pathway using the neurotoxin, 6-hydroxyDA (6-OHDA). The self-referencing amperometric recording method employs Nafion-coated with and without m-phenylenediamine recording sites that through real-time subtraction allow for simultaneous measures of tonic DA levels and transient changes due to depolarization and amphetamine-induced release. The recording method achieves low-level measures of both tonic and phasic DA with decreased recording drift allowing for enhanced sensitivity normally not achieved with electrochemical sensors in vivo.

Highlights

Dopamine (DA) serves as a principle neurotransmitter for essential brain pathways that regulate affect, cognition, movement, and reward [1]
The applied potential of +0.35 V was chosen because it achieved a robust DA response while limiting oxidation of species that could be present like H2 O2 or NO that oxidize at higher potentials
The present study has demonstrated that a differential recording method can be employed in DA-rich areas of the rat striatum and nucleus accumbens to reliably measure tonic and phasic

Summary

Introduction

Dopamine (DA) serves as a principle neurotransmitter for essential brain pathways that regulate affect, cognition, movement, and reward [1]. Analytical approaches for the detection and quantification of extracellular levels of brain DA have been of the utmost importance for elucidating its role as a modulatory neurotransmitter and for advancing our understanding of how brain DA systems impact ongoing behavior [2,3]. Extracellular DA is present in both synaptic and extrasynaptic pools, which enables differential modulation of pre- and postsynaptic neuronal signaling [4]. Current analytical techniques are unable to measure both tonic and phasic levels of DA simultaneously and, require the use of a complementary approach to investigate the “missing” component of extracellular neurotransmitter dynamics. Ascorbic acid and other anions (A) Dopamine.

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