The Potential Role of Serotonin1A Receptors in Post-weaning Social Isolation-Induced Abnormal Behaviors in Rodents

Post-weaning social isolation in mice induces behavioral abnormalities such as hyperactivity, aggression, depression- and anxiety-like behaviors, deficits of prepulse inhibition, and reduced pain sensitivity to the noxious stimuli. Then, this mouse is considered to be a model of psychiatric disorders including schizophrenia. We have found that serotonin (5-HT)(1A)-receptor ligands attenuate these abnormalities, suggesting the pharmacological role of the receptor in treatment of psychiatric disorders. Furthermore, we have recently found that isolation-reared mice show social encounter induced hyperactivity, a novel phenotype of the abnormal behaviors, and the hyperactivity is triggered by activation of the serotonergic system from the dorsal raphe to the frontal cortex. This review summarizes the effects of 5-HT1A receptor ligands on aggressive behavior, deficits of prepulse inhibition, reduced pain sensitivity to the noxious stimuli, and encounter-induced hyperactivity in social isolation reared mice. These findings suggest that the 5-HT1A receptor is a potential target molecule for treatment of psychiatric disorders and pain.