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Calretinin expression in the chick brainstem auditory nuclei develops and is maintained independently of cochlear nerve input
Author(s) -
Parks Thomas N.,
Code Rebecca A.,
Taylor Dwan A.,
Solum Derek A.,
Strauss Kenneth I.,
Jacobowitz David M.,
Winsky Lois
Publication year - 1997
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/(sici)1096-9861(19970623)383:1<112::aid-cne9>3.0.co;2-4
Subject(s) - in situ hybridization , calretinin , biology , brainstem , cochlear nucleus , messenger rna , anatomy , cochlea , auditory system , inner ear , microbiology and biotechnology , neuroscience , immunohistochemistry , biochemistry , gene , immunology
The expression of the calcium‐binding protein calretinin (CR) in the chick brainstem auditory nuclei angularis (NA), laminaris (NL), and magnocelularis (NM) was studied during normal development and after deafening by surgical removal of the otocyst (embryonic precursor of the inner ear) or columella (middle ear ossicle). CR mRNA was localized by in situ hybridization by using a radiolabeled oligonucleotide chick CR probe. CR immunoreactivity (CR‐IR) was localized on adjacent tissue sections. CR mRNA signal in the auditory nuclei was expressed at comparable levels at embryonic day (E)9 and E11 and increased thereafter to reach the highest levels in posthatch chicks. CR‐IR neurons were apparent in NM and NA at E11 and in NL by E13, and CR‐IR increased in all three auditory nuclei thereafter. Neither unilateral nor bilateral otocyst removal caused detectable changes in the intensity of CR mRNA expression or CR‐IR in the auditory nuclei at any of the several ages examined. Similarly, columella removal at posthatching day 2 or 3 failed to significantly affect CR mRNA or CR‐IR levels at 3 hours, 1 day, or 3–4 days survival times. We conclude that cochlear nerve input is not necessary for expression of either calretinin mRNA or protein and that the profound decrease in sound‐evoked activity caused by columella removal does not affect the maintenance of CR expression after hatching. J. Comp. Neurol. 383:112–121, 1997. © 1997 Wiley‐Liss,Inc.