In cholinergic neurons, the hemicholinium-3 (HC-3) sensitive, Na+/Cl--coupled, high affinity choline cotransporter (CHT) provides choline for acetylcholine (ACh) biosynthesis. The activity of CHT is tightly regulated by neuronal activity, and second messengers. Recent studies reveal that CHT is located in multiple compartments, including the plasma membrane and synaptic vesicles (Ferguson et al., Abstract, SFN 2002). We also have reported a change in the surface distribution of CHT proteins in response to protein kinase C (PKC) activation and protein phosphatase PP1/PP2A inhibition in the mouse striatum (Gates et al., Abstract, SFN 2002). In the present investigation, we examine the influence of electrical stimulation (square wave pulses, 50 Volts, 10 msec pulse duration) on CHT function in superfused mouse striatal slices. Crude striatal synaptosomes were prepared at the end of the stimulation period, and CHT-mediated choline uptake was measured using [3H] choline. Electrical stimulation at 5Hz for 30 min...