title: Age-related changes in calbindin D-28k and calretinin immunoreactivity in the inferior colliculus of CBA/CaJ and C57Bl/6 mice.
abstract: This study examines calbindin D-28k and calretinin immunoreactivity in the inferior colliculus (IC) of young and old mice of two strains. The CBA/CaJ mouse maintains good hearing until very late in life, whereas the C57Bl/6 strain exhibits severe sensorineural hearing loss at an early age. Young and old mice of both strains were selected with matching auditory brainstem response audiograms and gap detection thresholds. Brain sections were reacted with anti-calbindin D-28k (CB) and anti-calretinin (CR). Staining patterns were characterized and cell counts performed. CB immunoreactivity was high only in the nucleus of the commissure (NCO); counts revealed a 22.3% decrease in the number of CB+ cells in old CBA mice and a 25.1% decrease in old C57 mice. Calretinin immunoreactivity was high in the pericentral regions of the IC, but the central nucleus was devoid of CR+ cells. The dorsal cortex, lateral nucleus, and NCO showed increases of 42.3, 49.0, and 61%, respectively, in the number of CR+ cells, but only in the old CBA mice. No significant change was observed in the old C57 mice. Whereas decreases in CB immunoreactivity are common with age, this study is the first to report an age-related increase in CR immunoreactivity in the auditory system. The increase in CR+ cells is a possible compensatory adaptation to the decrease in CB+ cells. That the number of CR+ cells remains constant with age in C57 mice suggests this compensation may depend upon stimulus-driven activity, but this requires further study.
authors.affiliation: Department of Surgery, University of Rochester School of Medicine and Dentistry, New York 14642, USA.
authors.forename: M L
authors.initials: ML
authors.lastname: Zettel
authors.forename: R D
authors.initials: RD
authors.lastname: Frisina
authors.forename: S E
authors.initials: SE
authors.lastname: Haider
authors.forename: W E
authors.initials: WE
authors.lastname: O'Neill
mesh_terms: D000161:Acoustic Stimulation; D000375:Aging / Q000378:metabolism*; D000818:Animals; D064032:Calbindin 2; D064026:Calbindins; D003638:Deafness; D016057:Evoked Potentials, Auditory, Brain Stem; D006309:Hearing; D007150:Immunohistochemistry; D007245:Inferior Colliculi / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000502:physiology; D064030:S100 Calcium Binding Protein G / Q000032:analysis / Q000378:metabolism*; D013045:Species Specificity
chemical_list: C576511:Calb2 protein, mouse; D064032:Calbindin 2; D064026:Calbindins; D009419:Nerve Tissue Proteins; D064030:S100 Calcium Binding Protein G