title: Mapping of the colocalization of calretinin and tyrosine hydroxylase in the rat substantia nigra and ventral tegmental area.
abstract: The distribution of calretinin (CR), a calcium binding protein, was compared with that of tyrosine hydroxylase (TH), the rate-limiting enzyme in the synthesis of dopamine, throughout the rostrocaudal extent of the rat substantia nigra (SN) and ventral tegmental area (VTA). After mapping the cells using double-labelling immunofluorescence, it was possible to distinguish three distinct cell types: cells immunoreactive for CR only, cells immunoreactive for TH only, and cells in which the two proteins were colocalized (CR + TH). Colocalized cells in rat brain sections comprised approximately 40-55% of the fluorescent labelled cells in the SN compacta, 30-40% in the VTA, and 55-80% in the SN lateralis. Colocalized cells in the SN reticulata were infrequent except in the more caudal sections where a majority of the TH-immunoreactive cells also contained CR. The percentage of CR cells that contained TH was approximately 80% in the SN compacta and averaged 65% in the VTA. Overall, the percentage of TH-immunoreactive cells which also contained CR was approximately 50% in the SN compacta and 45% in the VTA. These data reveal a significant degree of colocalization of CR in dopamine-producing cells of the SN and VTA and suggest the need for studies concerning the fate of these individual cell types following experimental manipulations.
authors.affiliation: Laboratory of Clinical Sciences, National Institute of Mental Health, Bethesda, MD 20892.
authors.forename: K R
authors.initials: KR
authors.lastname: Isaacs
authors.forename: D M
authors.initials: DM
authors.lastname: Jacobowitz
mesh_terms: D000818:Animals; D001931:Brain Mapping; D064032:Calbindin 2; D004298:Dopamine / Q000276:immunology / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D007150:Immunohistochemistry; D008297:Male; D009419:Nerve Tissue Proteins / Q000276:immunology / Q000378:metabolism*; D051381:Rats; D064030:S100 Calcium Binding Protein G / Q000276:immunology / Q000378:metabolism*; D013378:Substantia Nigra / Q000201:enzymology / Q000378:metabolism* / Q000502:physiology; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*; D017557:Ventral Tegmental Area / Q000201:enzymology / Q000378:metabolism* / Q000502:physiology
chemical_list: C576512:Calb2 protein, rat; D064032:Calbindin 2; D009419:Nerve Tissue Proteins; D064030:S100 Calcium Binding Protein G; D014446:Tyrosine 3-Monooxygenase; D004298:Dopamine