Immunohistochemical Study of Insulin-Like Growth Factor-I (IGF-I) in the Olivocerebellar System of Developing and Adult Rats / 대한해부학회지

ABSTRACT

The developmental topography of olivocerebellar projection is not fully understood. Insulin-like growth factor-I (IGF-I) plays important roles in neural development. This study examined to observe IGF-I-like immunoreactivity (IGF-I IR) in the cerebellum and inferior olive of postnatal developing and adult rats. IGF-I immunoreactive Purkinje cells exhibited spatially and temporally regulated distribution which correlates with climbing fiber development. At birth a few IGF-I immunoreactive Purkinje cells were stained weakly only in the ventral vermis. By P7, all Purkinje cells of the vermis and hemispheres were positively labelled. A subpopulation of Purkinje cells lost IGF-I IR, and IGF-I IR Purkinje cells were divided into discrete population arranged in sagittal strips which were separated by non-reactive Purkinje cells. In the inferior olive, neurons showed IGF-I IR between P0 and P7. By P10 the inferior olive neurons were all negative for IGF-IR and this was mantained to adulthood. The IGF-I IR for Purkinje cell and inferior olive coincides with climbing fiber development and thus the results of this study support the hypothesis that IGF-I is specially involved in the refinement of olivocerebellar topography during synaptogenesis.