ASSESSMENT OF SEROTONERGIC TRANSMISSION DURING SOCIAL INTERACTION IN MICE

Vishwakarma Sarandeep*, Verma Prakash Bhanu

Social behavior deficits are characteristic features of several neuropsychiatric and neurodevelopmental disorders, including autism spectrum disorder, schizophrenia, and social anxiety disorder. Serotonin (5-hydroxytryptamine; 5-HT) plays a critical role in regulating social cognition and behavior; however, the specific contribution of serotonergic signaling to sociability remains incompletely understood. The present study investigated the role of serotonergic neurotransmission in social interaction behavior using the sociability test in Swiss albino mice. Mice were treated intraperitoneally with the serotonin precursor 5-hydroxy-L-tryptophan (5-HTP; 1, 5, 25, and 75 mg/kg), the serotonergic receptor antagonist metergoline (1, 5, and 10 mg/kg), or the serotonin-releasing agent fenfluramine (1, 5, and 10 mg/kg). Social behavior was assessed using the three-chamber sociability apparatus. Data were analyzed using one-way analysis of variance (ANOVA) followed by Newman–Keuls post hoc testing. Administration of 5-HTP produced a significant enhancement of sociability at 75 mg/kg [F(4,35)=39.93, p<0.05], whereas lower doses were ineffective. Metergoline significantly reduced social interaction [F(2,15)=61.06, p<0.0001], indicating the involvement of endogenous serotonergic activity in maintaining normal social behavior. Fenfluramine significantly altered social interaction behavior [F(2,15)=47.16, p<0.0001] and modified the effects of 5-HTP. Furthermore, fenfluramine significantly influenced 5-HTP-induced sociability, whereas metergoline failed to alter the effect of 5-HTP [F(3,20)=51.16, p<0.0001]. These findings demonstrate that serotonergic neurotransmission plays a crucial role in regulating social behavior in mice. Enhancement of central serotonin levels improves sociability, whereas serotonergic receptor modulation significantly influences social interaction. The serotonergic system may therefore represent a promising therapeutic target for social deficits associated with neuropsychiatric disorders.