A potential reservoir of immature dopaminergic replacement neurons in the adult mammalian olfactory bulb

Pflugers Arch. 2009 Feb;457(4):899-915. doi: 10.1007/s00424-008-0535-0. Epub 2008 Nov 15.


A significant fraction of the interneurons added in adulthood to the glomerular layer (GL) of the olfactory bulb (OB) are dopaminergic (DA). In the OB, DA neurons are restricted to the GL, but using transgenic mice expressing eGFP under the tyrosine hydroxylase (TH) promoter, we also detected the presence of TH-GFP+ cells in the mitral and external plexiform layers. We hypothesized that these could be adult-generated neurons committed to become DA but not yet entirely differentiated. Accordingly, TH-GFP+ cells outside the GL exhibit functional properties (appearance of pacemaker currents, synaptic connection with the olfactory nerve, intracellular chloride concentration, and other) marking a gradient of maturity toward the dopaminergic phenotype along the mitral-glomerular axis. Finally, we propose that the establishment of a synaptic contact with the olfactory nerve is the key event allowing these cells to complete their differentiation toward the DA phenotype and to reach their final destination.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Action Potentials / physiology
  • Animals
  • Chlorides / metabolism
  • Dopamine / metabolism*
  • Eye Proteins / genetics
  • Eye Proteins / metabolism
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / metabolism
  • Mice
  • Mice, Transgenic
  • Neurons / cytology
  • Neurons / metabolism*
  • Olfactory Bulb / cytology*
  • Olfactory Bulb / metabolism
  • PAX6 Transcription Factor
  • Paired Box Transcription Factors / genetics
  • Paired Box Transcription Factors / metabolism
  • Patch-Clamp Techniques
  • Receptors, Glutamate / metabolism
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism
  • Tyrosine 3-Monooxygenase / genetics
  • Tyrosine 3-Monooxygenase / metabolism


  • Chlorides
  • Eye Proteins
  • Homeodomain Proteins
  • PAX6 Transcription Factor
  • Paired Box Transcription Factors
  • Pax6 protein, mouse
  • Receptors, Glutamate
  • Recombinant Fusion Proteins
  • Repressor Proteins
  • Tyrosine 3-Monooxygenase
  • Dopamine