[Hippocampal serotonin 1A receptor and memory function].

Recent studies have indicated that the serotonergic system plays important roles in memory functions. To clarify this relationship, we examined 5-HT1A receptors using positron emission tomography (PET) with [11C]WAY-100635 and assessed the relationship with memory functions. To interpret the pharmacological implications, we administered the 5-HT1A agonist tandospirone to subjects and investigated the effect of the stimulation of 5-HT1A receptors on cognitive function together with the neuroendocrinological response. There was a significant negative correlation between explicit memory function and 5-HT1A receptor binding localized in the bilateral hippocampus where the postsynaptic 5-HT1A receptors are enriched. Furthermore, we found that the administration of tandospirone dose-dependently impaired explicit verbal memory, while other cognitive functions showed no significant changes. The results show that the postsynaptic 5-HT1A receptors localized in the hippocampal formation have a negative influence on explicit memory function.