Biomedical Engineering Reference
In-Depth Information
31
Real-Time Measurements of Phasic Changes
in Extracellular Dopamine Concentration in Freely
Moving Rats by Fast-Scan Cyclic Voltammetry
Paul E. M. Phillips, Donita L. Robinson, Garret D. Stuber,
Regina M. Carelli, and R. Mark Wightman
1. Introduction
Rapid, transient changes in extracellular dopamine concentrations following
salient stimuli in freely moving rats have recently been detected using fast-
scan cyclic voltammetry
(1
,
2)
. This type of neurotransmission had not been
previously observed (for any neurotransmitter), but has been implicated by
electrophysiological studies. Schultz et al.
(3)
reported synchronous burst fi ring
of midbrain dopaminergic neurons following presentation of liquid reinforcers
or associated cues. Such fi ring patterns would predictably produce transient
(lasting no more than a few seconds), high concentrations (high nanomolar)
of extracellular dopamine in terminal regions. This phasic dopaminergic
neurotransmission has been heavily implicated in associative learning and
reward processing, and therefore may prove essential in understanding the
reinforcing actions of drugs of abuse.
Fast-scan cyclic voltammetry is a real-time electrochemical technique
that can detect dopamine by its redox properties. It is capable of monitoring
monoaminergic neurotransmission in the brain on a subsecond time scale while
providing chemical information on the analyte. This chapter describes how
the properties of fast-scan cyclic voltammetry make it uniquely suitable for
making chemical measurements of phasic dopaminergic neurotransmission
in freely moving animals. To emphasize the potential of this technique, three
examples of its use are highlighted. First we describe experiments testing
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