The effects of various cognition-enhancing drugs on in vitro rat hippocampal synaptosomal sodium dependent high affinity choline uptake.

The purpose of the present study was to compare the effect of seven drugs, that have been reported to enhance cognitive functions, on rat hippocampal cholinergic neuronal activity. The latter was assessed by measuring the effects of the drugs on in vitro sodium-dependent high affinity choline uptake (HACU) into rat hippocampal synaptosomes 30 minutes after their in vivo administration. 3,4-Diaminopyridine (0.1 mg/kg IP), like pramiracetam (44 and 88 mg/kg IP), increased HACU with higher or lower doses being ineffective. Centrophenoxine (100 mg/kg IP) decreased HACU. Piracetam (100 and 500 mg/kg IP), aniracetam (10-200 mg/kg PO), lysine vasopressin (0.005-0.05 mg/kg IM) and 4-aminopyridine (0.01-3.0 mg/kg IP) were ineffective. The results indicate that 3,4-diaminopyridine and centrophenoxine, like pramiracetam may be increasing cognitive function in part by affecting hippocampal cholinergic neuronal activity. In addition, the findings indicate the usefulness of using in vitro HACU as a biochemical measurement to assess the potential effect of cognitive-enhancing drugs on cholinergic neuronal activity in vivo.