Immunoreactivity of calcium-binding proteins in the central auditory nervous system of aged rats.
OBJECTIVE
While many factors contribute to aging, changes in calcium homeostasis and calcium related neuronal processes are likely to be important. High intracellular calcium is toxic to cells and alterations in calcium homeostasis are associated with changes in calcium-binding proteins, which confine free Ca(2+). We therefore assayed the expression of the calcium binding proteins calretinin and calbindin in the central auditory nervous system of rats.


METHODS
Using antibodies to calretinin and calbindin, we assayed their expression in the cochlear nucleus, superior olivary nucleus, inferior colliculus, medial geniculate body and auditory cortex of young (4 months old) and aged (24 months old) rats.


RESULTS
Calretinin and calbindin staining intensity in neurons of the cochlear nucleus was significantly higher in aged than in young rats (p<0.05) The number and staining intensity of calretinin-positive neurons in the inferior colliculus, and of calbindin-positive neurons in the superior olivary nucleus were greater in aged than in young rats (p<0.05).


CONCLUSIONS
These results suggest that auditory processing is altered during aging, which may be due to increased intracellular Ca(2+) concentration, consequently leading to increased immunoreactivity toward calcium-binding proteins.
Hong
Seok Min
SM
Department of Otorhinolaryngology and Head and Neck Surgery, College of Medicine, KyungHee University, Seoul, Korea.
Chung
Seung Young
SY
Park
Moon Sun
MS
Huh
Young Buhm
YB
Park
Moon Suh
MS
Yeo
Seung Gun
SG