FETAL VENTRAL MESENCEPHALIC CELL-SUSPENSION GRAFTS TO THE 6-HYDROXYDOPAMINE-LESIONED RAT REDUCE THE RATE OF DOPAMINE UPTAKE IN THE CONTRALATERAL STRIATUM

The present study employed fast cyclic voltammetry, at carbon-fibre mi croelectrodes, to monitor and compare the rate of dopamine uptake in t he rat striatum contralateral to (a) the 6-hydroxydopamine (6-OHDA)-le sioned/grafted striatum and (b) the 6-OHDA-lesioned/sham grafted stria tum. Cell suspensions of foetal rat ventral mesencephalic tissue were grafted into the dopamine-depleted striatum of unilaterally 6-OHDA-les ioned rats. Six weeks after grafting, animals with functional, mature grafts were monitored for dopamine elimination in the contralateral st riatum following electrical stimulation of the median forebrain bundle , before and after treatment with the dopamine uptake inhibitor GBR 12 909. Compared to animals with sham grafts, amphetamine-amplified rotat ional behaviour was significantly reduced in animals with grafts of fo etal ventral mesencephalic tissue. Fast cyclic voltammetric measuremen ts followed by evaluation with the aid of a kinetic model revealed tha t in grafted animals, the rate of dopamine uptake via the high affinit y uptake mechanism, following treatment with GBR 12909, was significan tly reduced when compared to sham grafted animals.