Buspirone

Buspirone is a partial agonist of the 5-HT₁A receptor and can bind to both presynaptic 5-HT₁A autoreceptors and postsynaptic 5-HT₁A receptors in the central nervous system. In the early phase of action, stimulation of presynaptic 5-HT₁A autoreceptors suppresses serotonin release, temporarily reducing serotonin activity. With long-term use, the sensitivity of presynaptic 5-HT₁A autoreceptors decreases through desensitization, leading to increased serotonin release into the synaptic cleft and affecting anxiety- and mood-related neural regulation. Buspirone also exerts partial agonist activity at postsynaptic 5-HT₁A receptors, contributing to anxiolytic-related neural effects. In addition, it has mild antagonistic activity at dopamine D₂ receptors.