Choline uptake and permanent memory storage.

The uptake of 3H-choline and its incorporation into 3H-acetylcholine was studied in vitro on hippocampus slices obtained from animals showing a good or poor long-term memory. The animals were selected on the basis of their retention performance when tested by a brightness discrimination model. The 3H-choline uptake and the incorporation of 3H-choline into 3H-acetylcholine was higher in hippocampus slices from animals showing good retention compared to those from animals with poor retention. The level of high affinity uptake of choline into hippocampus slices may serve as an indicator of the cholinergic activity in this structure under in vitro conditions. The present findings suggest that individual differences in the activity level of the hippocampal cholinergic system do exist and are capable of influencing the retention of the individual animals to a variable degree.