Using fast-scan cyclic voltammetry to investigate somatodendritic dopamine release

Midbrain dopamine (DA) neurons of the substantia nigra (SN, “A9”) and adjacent ventral tegmental area (VTA, “A10”) are critical to a range of CNS functions, including motor facilitation by the basal ganglia and the regulation of motivation by natural rewards as well as by drugs of addiction. A characteristic shared by DA cells in the SN and VTA is that they release DA locally from somatodendritic regions1-4 as well as from their axonal projections. There is evidence for release from soma5 as well as from dendrites.2,6 Somatodendritic release of neurotransmitter is not restricted to DA neurons; rather, neurons found throughout the brain can signal via the somatodendritic release of neurotransmitters, including GABA and glutamate as well as neuropeptides.7,8 Somatodendritic neurotransmission operates both at a synaptic level and by more paracrine/autocrine- like modes to offer neuronal cross-talk as well as self- or auto-feedback control.7,8 This chapter will focus specifically on the somatodendritic release of DA within the midbrain and how voltammetric methods, particularly fast-scan cyclic voltammetry (FCV), have been used to explore its characteristics.