Dopaminergic Neuron

Neuron dopaminergicum

Modulatory midbrain neuron whose dopamine release to striatum and cortex signals reward prediction error and enables smooth voluntary movement.

Function

The substantia nigra pars compacta (SNc) population projects to striatum (nigrostriatal pathway) and is essential for initiating voluntary movement. The ventral tegmental area (VTA) population projects to prefrontal cortex and nucleus accumbens (mesocortical and mesolimbic pathways) and signals reward prediction error.

Morphology

An elongated ovoid soma (~25 µm), a sparse dendritic tree, and an exceptionally long, highly branched axon studded with varicosities at which dopamine is released by volume transmission.

Specification

  • Neurotransmitter: Dopamine
  • Co-transmitters: Glutamate (VGLUT2+ subsets); GABA (subset, especially nigrostriatal)
  • Receptors: D2 (Autoreceptors); NMDA; GABA
  • Location: Midbrain, substantia nigra pars compacta and ventral tegmental area.
  • Projections: Striatum; Prefrontal cortex
  • Firing: Tonic (pacemaker); Phasic (bursting)
  • Markers: TH; SLC6A3/DAT; DDC/AADC; SLC18A2/VMAT2; KCNJ6/GIRK2 (SNc); CALB1/calbindin (VTA)
  • Developmental origin: Mesencephalon (Floor plate)
  • Disease: SNc dopaminergic neurons selectively degenerate in Parkinson's disease; by the time motor symptoms appear, ~60% of them are already lost.
  • Cell Ontology: CL:0000700

References

  1. Schultz W, Dayan P, & Montague PR (1997). A neural substrate of prediction and reward.. Science 275 PMID 9054347
  2. Fearnley JM & Lees AJ (1991). Ageing and Parkinson's disease: substantia nigra regional selectivity.. Brain 114: 2283–2301 114 ( Pt 5) PMID 1933245

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