Midbrain dopaminergic neurons in the mouse: Computer-assisted mapping

Abstract

The dopaminergic (DA) neurons in the midbrain play a role in cognition, affect and movement. The purpose of the present study was to map and quantify the number of DA neurons in the midbrain, within the nuclei that constitute cell groups A8, A9 and A10, in the mouse. Two strains of mice were used; the C57BL/6 strain was chosen because it is commonly used in neurobiological studies, and the FVB/N strain was chosen because it is used frequently in transgenic studies. DA neurons were identified, in every fifth 20-microns-thick coronal section, using an antibody against tyrosine hydroxylase. Cell locations were entered into a computer imaging system. The FVB/N strain has 42% more midbrain DA neurons than the C57BL/6 strain; on one side of the brain there were 15,135 +/- 356 neurons (mean +/- S.E.M.) in the FVB/N strain, and 10,645 +/- 315 neurons in the C57BL/6 strain. In both strains, approximately 11% of the neurons were located in nucleus A8 (the DA neurons in the retrorubral field), 38% in nucleus A9 (the DA neurons in the substantia nigra pars compacta, pars reticulata, and pars lateralis), and 51% in nucleus A10 (the DA neurons in midline regions such as the ventral tegmental area, central linear nucleus, and interfascicular nucleus). The number of midbrain DA cells, and their distribution within the three nuclear groups, is discussed with respect to findings in other species.

Exendin-4 protects dopaminergic neurons by inhibition of microglial activation and matrix metalloproteinase-3 expression in an animal model of Parkinson's disease

“…Each midbrain section was viewed at low power (40! ), and the SNpc was outlined using the set of anatomical landmarks defined previously (Nelson et al 1996) and according to the atlas of Franklin & Paxinos (2001). The number of TH-stained cells was then counted at high power (400!).…”

Neurogenin2 identifies a transplantable dopamine neuron precursor in the developing ventral mesencephalon

“…Dopaminergic neurons make up defined sets of cells in the hypothalamus, olfactory bulb and retina; however, the bulk of the DA neurons are found in the VM (10,20,22).…”

Molecular and functional differences in voltage-activated sodium currents between GABA projection neurons and dopamine neurons in the substantia nigra

“…Taken together, these results indicate that Na V channels expressed in fast-spiking SNr GABA neurons and slow-spiking SNc DA neurons are tailored to support their different spiking capabilities. basal ganglia; substantia nigra; transient sodium current; persistent sodium current; resurgent sodium current AS A KEY COMPONENT OF THE basal ganglia motor circuitry, substantia nigra (SN) is populated largely by two types of projection neurons: GABA neurons in SN pars reticulata (SNr) and dopamine (DA) neurons in SN pars compacta (SNc) and also in SNr (Bolam et al 2000;Deniau et al 2007; GonzalezHernandez and Rodriguez, 2000;Nelson et al 1996; Parent et al. 2000).…”

“…AS A KEY COMPONENT OF THE basal ganglia motor circuitry, substantia nigra (SN) is populated largely by two types of projection neurons: GABA neurons in SN pars reticulata (SNr) and dopamine (DA) neurons in SN pars compacta (SNc) and also in SNr (Bolam et al 2000;Deniau et al 2007;GonzalezHernandez and Rodriguez, 2000;Nelson et al 1996;Parent et al 2000). SNr GABA neurons and SNc DA neurons have strikingly different firing properties.…”