Effects of nucleotides on learning and memory in a Morris water maze test in normal and basal forebrain-lesioned rats

The effects of nucleotides on learning and memory were studied in normal an d basal forebrain-lesioned rats using a Morris water maze test. Chronic ora l administration of a nucleotide mixture (500 mg/kg), containing an equal w eight of the disodium salts of adenosine 5'-monophosphate, guanosine 5'-mon ophosphate, inosine 5'-monophosphate, cytidine 5'-monophosphate, and uridin e 5'-monophosphate facilitated learning acquisition in normal rats. In basa l forebrain-lesioned rats, administration of the nucleotide mixture showed a tendency to improve learning acquisition, and memory retrieval. In the bi ochemical studies, no significant changes were observed in brain choline an d acetylcholine levels by treatment with the nucleotide mixture at the dose s tested in both normal and basal forebrain-lesioned rats. The nucleotides did not affect the monoaminergic systems in normal rats, but did cause some changes in these systems in basal forebrain-lesioned rats. The present stu dies indicate that nucleotides ameliorate learning and memory processes in normal rats, but not in basal forebrain-lesioned rats, and they also modula te the activity of the central monoaminergic systems under certain conditio ns.