Mapping of the colocalization of calretinin and tyrosine hydroxylase in the rat substantia nigra and ventral tegmental area

• Published in: Experimental brain research 1994-05, Vol.99 (1), p.34-42
• Main Authors: ISAACS, K. R, JACOBOWITZ, D. M
• Format: Article
• Language: English
• Subjects: Anatomy; Animals; Biological and medical sciences; Brain Mapping; Calbindin 2; Central nervous system; Dopamine - immunology; Dopamine - metabolism; Fluorescent Antibody Technique; Fundamental and applied biological sciences. Psychology; Immunohistochemistry; Male; Nerve Tissue Proteins - immunology; Nerve Tissue Proteins - metabolism; Rats; S100 Calcium Binding Protein G - immunology; S100 Calcium Binding Protein G - metabolism; Substantia Nigra - enzymology; Substantia Nigra - metabolism; Substantia Nigra - physiology; Tyrosine 3-Monooxygenase - metabolism; Ventral Tegmental Area - enzymology; Ventral Tegmental Area - metabolism; Ventral Tegmental Area - physiology; Vertebrates: nervous system and sense organs
• ISSN: 0014-4819; 1432-1106
• DOI: 10.1007/bf00241410

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.