Postnatal calcitonin gene-related peptide in the superior olivary complex.
The purpose of this study was to investigate quantitatively the distribution of calcitonin gene-related peptide (CGRP)-positive neurons within the superior olivary complex (SOC) at various postnatal ages. In the lateral superior olive (LSO), most if not all, CGRP-positive cells correspond to the cholinergic portion of the lateral olivocochlear system which innervates the cochlea. Brains from 1-day old (P1) through juvenile (P30) hamsters were used. At all ages, CGRP-positive neurons were seen throughout the various nuclei of the SOC. There was a dramatic shift in the distribution of CGRP-positive neurons from being predominantly periolivary to being predominantly confined within the LSO. The number of CGRP-positive neurons clearly increased as a function of increasing age. At the earliest postnatal ages, the LSO contained few if any immunostained cells, whereas at later ages the LSO contained the majority (greater than 70%) of the immunostained cells. Assuming that these CGRP-positive cells within the LSO correspond to olivocochlear neurons, these data suggest that in hamsters the lateral olivocochlear system may be immature at birth up until the second postnatal week.
Simmons
D D
DD
Department of Biology, UCLA 90024-1606.
Raji-Kubba
J
J
D000375:Aging / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D001306:Auditory Pathways / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D001933:Brain Stem / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D015740:Calcitonin Gene-Related Peptide / Q000276:immunology / Q000378:metabolism*; D017626:Cochlear Nucleus / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D006224:Cricetinae; D007150:Immunohistochemistry; D008647:Mesocricetus; D009474:Neurons / Q000378:metabolism; D009847:Olivary Nucleus / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*
D015740:Calcitonin Gene-Related Peptide