Localisation of insulin-like growth factor-I (IGF-I) immunoreactivity in the olivocerebellar system of developing and adult rats.
The molecular mechanisms which underlie the development of the olivocerebellar topography are not fully understood. Insulin-like growth factor-I (IGF-I) is a growth factor known to play important roles in neural development and it has been identified within the cerebellum and the inferior olive. To assess the contribution of IGF-I to the development of climbing fibre topography, the distribution of IGF-I-like immunoreactivity (IGF-I IR) was identified in the cerebellar cortex and inferior olive of rats, 0, 3, 5, 7, 10, 15, 21, 28 and 90 days old. In the cerebellar cortex, IGF-I IR was localised solely to Purkinje cells and its distribution was spatially and temporally regulated in a manner which coincides with climbing fibre development. At birth, weak IGF-I IR was detected in a few Purkinje cells in the ventral vermis. More Purkinje cells became positive until at postnatal day 7(P7) all Purkinje cells displayed IGF-I IR. Subsequently, a subpopulation of Purkinje cells lost their reactivity for IGF-I to leave IGF-I-positive cells organised into sagittal bands by P15. IGF-I IR was also seen in all subdivisions of the inferior olive between birth and P10 in a distribution which paralleled the maturation of the inferior olive. The Purkinje cell and inferior olivary IGF-I IR parallels climbing fibre development and thus the results of this study support the hypothesis that IGF-I is involved in the development of climbing fibre topography.
Sherrard
R M
RM
Neuroscience Laboratory, School of Life Science, Queensland University of Technology, Brisbane, Australia. r.sherrard@pop.qut.edu.au
Richardson
N A
NA
Sara
V R
VR
D000367:Age Factors; D000818:Animals; D000918:Antibody Specificity; D002531:Cerebellum / Q000737:chemistry / Q000166:cytology / Q000254:growth & development; D005260:Female; D007150:Immunohistochemistry; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000276:immunology*; D008297:Male; D009434:Neural Pathways; D009847:Olivary Nucleus / Q000737:chemistry* / Q000166:cytology / Q000254:growth & development; D011247:Pregnancy; D011689:Purkinje Cells / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar; D017526:Receptor, IGF Type 1 / Q000032:analysis
D007334:Insulin-Like Growth Factor I; D017526:Receptor, IGF Type 1