INSULIN-LIKE-GROWTH-FACTOR-I RESTORES MOTOR COORDINATION IN A RAT MODEL OF CEREBELLAR-ATAXIA

We tested the potential of insulin-like growth factor I (IGF-I) to ind uce functional recovery in an animal model of cerebellar ataxia becaus e this motor impairment is accompanied in humans and rodents by distin ct changes in several components of the IGF-I trophic system, Rats ren dered ataxic by deafferentation of the cerebellar cortex with 3-acetyl pyridine recovered motor function after IGF-I was administered, as det ermined by behavioral and electrophysiological tests. When treated wit h IGF-I, inferior olive neurons, the targets of the neurotoxin, were r escued to various degrees (from 92 to 27% of surviving neurons), depen ding on the time that treatment with IGF-I was initiated, Furthermore, full recovery was obtained regardless of the route by which the troph ic factor was administered (intraventricular or subcutaneous) even in rats with severe neuronal loss, These results suggest that human ataxi a could be treated with IGF-I by a simple procedure.