THERAPEUTIC MOTOR TRAINING INCREASES PARALLEL FIBER SYNAPSE NUMBER PER PURKINJE NEURON IN CEREBELLAR CORTEX OF RATS GIVEN POSTNATAL BINGE ALCOHOL EXPOSURE - PRELIMINARY-REPORT

Because therapeutic approaches to fetal alcohol effects in humans have been rare, this study explored the rehabilitative effect of complex m otor training on an animal model of binge drinking in the third trimes ter of human pregnancy. Neonatal alcohol exposure induces significant and permanent reductions in Purkinje and granule cell number accompani ed by impaired motor behavior in rats. The purpose of this study was t o determine: (1) whether the motor skill impairment caused by exposure to alcohol in the early postnatal period could be ameliorated by the learning of a set of complex motor tasks that had been demonstrated to cause synaptogenesis in the cerebellar cortex; and (2) the extent to which cerebellar neurons in alcohol-exposed (AE) rats exhibit synaptic plasticity. The AE group was given 4.5 g/kg/day of ethanol from postn atal days 4 to 9 via an artificial rearing procedure producing a mean peak blood alcohol level of 257 mg/dl. Control groups consisted of a g astrostomy control (GC) group, that received an isocaloric mixture of maltose/dextrin instead of ethanol, and a suckle control (SC) group, t hat was reared normally by dams. At similar to 6 months of age, animal s from the three groups were assigned either to a rehabilitation condi tion (RC; that received 10 days of training on the motor tasks) or to an inactive condition (IC; where rats stayed in isolation in their cag es). Although SC rats were significantly faster to complete the course in the first 5 days of training, there were no differences in ability to perform among animals from all three groups-SC, GC, and AE-at the end of the training period. Unbiased stereological techniques were use d to obtain estimates of the number of parallel fiber synapses/Purkinj e cell within the cerebellar paramedian lobule. Results showed that th e RC rats from the SC and AE groups had significantly more synapses/Pu rkinje cell than corresponding IC animals. These data demonstrate that rehabilitative intervention (complex motor training) can improve moto r performance impaired by postnatal alcohol exposure and that survivin g Purkinje neurons retain the capacity for synaptic plasticity.