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Effects of unilateral cochlea ablation on the distribution of calretinin mRNA and immunoreactivity in the guinea pig ventral cochlear nucleus
Author(s) -
Winsky Lois,
Jacobowitz David M.
Publication year - 1995
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.903540407
Subject(s) - calretinin , biology , axotomy , cochlea , cochlear nucleus , calcium binding protein , in situ hybridization , calbindin , messenger rna , dorsal cochlear nucleus , immunolabeling , anatomy , microbiology and biotechnology , nucleus , immunohistochemistry , neuroscience , central nervous system , medicine , calcium , immunology , gene , biochemistry
The predominantly neuronal, calcium‐binding protein calretinin is highly expressed in the guinea pig auditory system. Within the ventral cochlear nucleus (VCN), calretinin‐positive auditory nerve fibers terminate on many calretinin‐containing bushy, octopus, and multipolar cells. The abundance of calretinin in the cochlear nucleus provides an ideal system for examining the effects of altered neuronal input on the expression of this calcium‐binding protein. The present experiments examined the effects of unilateral cochlea ablation on calretinin immunoreactivity and mRNA levels in the VCN. Calretinin mRNA was labeled by in situ hybridization histochemistry using a radioactive oligonucleotide probe and was quantified by optical density measures on autoradiograms. Survival times of 1, 7, and 56 days postlesion were examined. The results revealed a consistent increase in calretinin mRNA in the rostral portion of the ipsilateral anterior VCN 1 day postlesion but no effect on calretinin mRNA in this region at 7 and 56 days postlesion. The intensity of immunohistochemical label was also increased at 1 and 7 days after surgery. In contrast, calretinin mRNA was not affected 1 day postlesion in the ipsilateral posterior VCN but was decreased at both 7 and 56 days postlesion. The decrease in calretinin mRNA in the posterior VCN at longer survival times was accompanied by decreased immunolabeling of fibers projecting from VCN cells to the superior olivary complex. These results suggest that calretinin gene expression is regulated in part by auditory nerve activity in some cochlear neurons but that additional factors related to the unique cellular milieu also control calretinin expression. © 1995 Wiley‐Liss, Inc.