Buspirone: review of its pharmacology and current perspectives on its mechanism of action.

Buspirone is a novel anxiolytic agent unrelated to the benzodiazepines in structure or pharmacologic properties. Extensive clinical studies have shown buspirone to be effective in the treatment of anxiety, with efficacy comparable to diazepam or clorazepate. Buspirone exhibits a unique pharmacologic profile in that it alleviates anxiety without causing sedation or functional impairment and does not promote abuse or physical dependence. Furthermore, preclinical studies have shown that buspirone does not possess anticonvulsant or muscle relaxant properties and does not interact significantly with central nervous system depressants. Biochemical and electrophysiologic studies indicate that buspirone alters monoaminergic and GABAergic systems in a manner different from that of the benzodiazepines. The uniform depressant action of the benzodiazepines upon serotonergic, noradrenergic, and dopaminergic cell firing may result from their facilitatory effect on gamma-aminobutyric acid and its known inhibitory influence in these monoaminergic areas. Unlike the benzodiazepines, buspirone exerts a differential influence upon monoaminergic neuronal activity, suppressing serotonergic activity while enhancing dopaminergic and noradrenergic cell firing. The mechanism of action of buspirone challenges the notion that only one neurotransmitter mediates anxiety. The interaction with multiple neurotransmitters at multiple brain sites suggests that buspirone may alter diverse activities within a "neural matrix of anxiety." In contrast to the benzodiazepines, buspirone orchestrates activity within this neural matrix to achieve effective treatment of anxiety while preserving arousal and attentional processes.