title: The midbrain dopaminergic system: anatomy and genetic variation in dopamine neuron number of inbred mouse strains.
abstract: The mesotelencephalic dopamine system is genetically variable and affects motor behavior, motivation, and learning. Here we examine the genetic variation of mesencephalic DA neuron number in a quasi-congenic RQI mouse strain and its background partner and in a recombinant inbred strain with different levels of mesencephalic tyrosine hydroxylase activity (TH/MES). We used B6.Cb4i5-alpha6/Vad, C57BL/6By, and CXBI, which are known to express high, intermediate, and low levels of TH/MES, respectively. Unbiased stereological sampling with optical disector counting methods were employed to estimate the number of TH-positive neurons in the A8-A9-A10 cell groups. Morphometric studies on the mesencephalic dopamine cell groups indicated that male mice of the B6.Cb4i5-alpha6/Vad strain were endowed with a significantly lower number of TH-positive cells than CXBI mice. In all strains studied, the right retrorubral field (A8 area) had a higher number of dopamine neurons compared to the left A8 area. The results suggest an inverse relationship between TH/MES and number of dopamine neurons in the A9-A10 cell groups and significant lateral asymmetry in the A8 cell group. A detailed anatomical atlas of the mesencephalic A8-A9-A10 dopaminergic cell groups in the mouse is also presented to facilitate the assignment of TH-positive neurons to specific cell groups.
authors.affiliation: Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, New Jersey 07102, USA. zaborszk@axon.rutgers.edu
authors.forename: L
authors.initials: L
authors.lastname: Zaborszky
authors.forename: C
authors.initials: C
authors.lastname: Vadasz
mesh_terms: D000818:Animals; D001931:Brain Mapping; D003433:Crosses, Genetic; D004298:Dopamine / Q000378:metabolism*; D005260:Female; D014644:Genetic Variation; D008297:Male; D008636:Mesencephalon / Q000033:anatomy & histology*; D051379:Mice; D008815:Mice, Inbred Strains / Q000235:genetics*; D009474:Neurons / Q000473:pathology; D019655:Quantitative Trait, Heritable; D011995:Recombination, Genetic; D014446:Tyrosine 3-Monooxygenase / Q000235:genetics*
chemical_list: D014446:Tyrosine 3-Monooxygenase; D004298:Dopamine