SEROTONIN AND ACETYLCHOLINE ARE CRUCIAL TO MAINTAIN HIPPOCAMPAL SYNAPSES AND MEMORY ACQUISITION IN RATS

Treatment with serotonin and acetylcholine depletors reduced the numbe r of synapses in the rat hippocampus. Animals that received the drug t reatment lost a substantial number of synapses and showed an apparent impairment in memory acquisition. Although the animals were behavioral ly impaired following the treatment, spatial memory was nonetheless ev entually attained despite the disappearance of longterm potentiation. These data suggest that synapses in the hippocampus that are normally maintained by serotonin and acetylcholine are crucial for normal acqui sition of spacial memory. The number of synapses maintained by biogeni c amines may be a basic mechanism for neurobehavioral plasticity. (C) 1997 Elsevier Science Ireland Ltd.