Choline uptake by glomerular synapses isolated from bovine cerebellar vermis.

[3H]Choline uptake was investigated in a highly enriched preparation of glomerular particles isolated from bovine cerebellar vermis. Kinetic analysis indicates that a high-affinity choline uptake system with a relatively low maximum uptake velocity is present. At a substrate concentration of 10(-7) M, [3H]choline uptake was shown to be sodium-dependent, hemicholinium-sensitive and non-reactive to increasing concentrations of unlabeled choline. These findings support the presence of a high-affinity choline uptake system in cerebellar glomeruli and would seem to be consistent with the suggestion that a small proportion of mossy fibers are cholinergic in this brain region.