Calretinin immunoreactivity in the magnocellular neurosecretory nuclei of the rat hypothalamus.
The distribution of calretinin-immunoreactivity in the magnocellular neurosecretory nuclei of the rat hypothalamus was studied using a polyclonal antibody and the avidin-biotin immunoperoxidase technique. Calretinin-immunoreactive neurons were observed in the supraoptic and paraventricular nuclei. Additionally, we detected for the first time, immunoreactive neurons located in the circularis and fornicals nuclei, and isolated positive neurons situated in the hypothalamic area located between the supraoptic and paracentricular nuclei. When these results were compared to those obtained in previous studies for another two calcium-binding proteins: calbindin D-28k and parvalbumin, two major differences may be concluded: a) a different distribution of calretinin, especially in the paraventricular nucleus, and b) an expression of calretinin lower than calbindin D-28k and higher than parvalbumin in the magnocellular hypothalamic nuclei. Of special interest is the fact that calretinin is one of the few markers which demonstrates predominantly parvicellular neurons in the paraventricular nucleus. Although the exact biochemical function of these three calcium-binding proteins remains unknown, their uneven and characteristic distributions strongly suggest that specific neuronal populations in the hypothalamus may use alternatively different calcium-sequestering molecules.
Arevalo
R
R
Department of Cellular Biology, University of Salamanca, Spain.
Sanchez
F
F
Alonso
J R
JR
Rubio
M
M
Aijon
J
J
Vazquez
R
R
D000818:Animals; D064032:Calbindin 2; D064026:Calbindins; D002135:Calcium-Binding Proteins / Q000276:immunology / Q000378:metabolism; D005260:Female; D007031:Hypothalamus / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D007150:Immunohistochemistry; D010286:Paraventricular Hypothalamic Nucleus / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D010320:Parvalbumins / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D064030:S100 Calcium Binding Protein G / Q000276:immunology / Q000378:metabolism*; D013495:Supraoptic Nucleus / Q000166:cytology / Q000276:immunology / Q000378:metabolism
C576512:Calb2 protein, rat; D064032:Calbindin 2; D064026:Calbindins; D002135:Calcium-Binding Proteins; D010320:Parvalbumins; D064030:S100 Calcium Binding Protein G