Role of 5-HT 1A receptors in the basolateral amygdala on 3,4-methylenedioxymethamphetamine-induced prosocial effects in mice.

3,4-methylenedioxymethamphetamine (MDMA), a recreational drug, induces euphoric sensations and psychosocial effects, such as increased sociability and empathy. Serotonin, also called 5-hydroxytryptamine (5-HT), is a neurotransmitter that has been associated with MDMA-induced prosocial effects. However, the detailed neural mechanisms remain elusive. In the present study, we investigated whether 5-HT neurotransmission in the medial prefrontal cortex (mPFC) and the basolateral nucleus of amygdala (BLA) is involved in MDMA-induced prosocial effects using the social approach test in male ICR mice. Systemic administration of (S)-citalopram, a selective 5-HT transporter inhibitor, before administration of MDMA failed to suppress MDMA-induced prosocial effects. On the other hand, systemic administration of the 5-HT _1A receptor antagonist WAY100635, but not 5-HT _1B , 5-HT _2A , 5-HT _2C , or 5-HT ₄ receptor antagonist, significantly suppressed MDMA-induced prosocial effects. Furthermore, local administration of WAY100635 into the BLA but not into the mPFC suppressed MDMA-induced prosocial effects. Consistent with this finding, intra-BLA MDMA administration significantly increased sociability. Together, these results suggest that MDMA induces prosocial effects through the stimulation of 5-HT _1A receptors in the BLA.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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