GLYCINE IMMUNOREACTIVITY AND RECEPTOR-BINDING IN THE COCHLEAR NUCLEUSOF C57BL 6J AND CBA/CAJ MICE - EFFECTS OF COCHLEAR IMPAIRMENT AND AGING/

Glycinergic neurons in the cochlear nucleus (CN) of C57BL/6J (C57) and CBA/CaJ (CBA) mice were studied by using immunocytochemical and recep tor-binding techniques. Adult C57 mice exhibit progressive cochlear pa thology as they age, whereas aging CBA mice retain good hearing. In th e CN of old C57 mice (18 months) with severe hearing loss, the number of glycine-immunoreactive neurons decreased significantly. The number (B-max) of strychnine-sensitive glycine receptors (GlyR) decreased sig nificantly in the dorsal CN of old C57 mice. Significant effects were not observed in the CN of middle-aged C57 mice (with less-severe heari ng loss) or in very old CBA mice (which do not exhibit severe hearing loss). The data suggest that the combination of severe hearing loss an d old age results in deficits in one or more inhibitory glycinergic ci rcuits in the CN. (C) 1997 Wiley-Liss, Inc.