Central serotonergic mechanisms on head twitch response induced by benzodiazepine receptor agonists

Intraperitoneal injection of benzodiazepine receptor agonists (estazolam, z opiclone, triazolam: 0.03-0.24 mmol/kg) induces the head twitch response (H TR). The present study was undertaken to examine the possible participation of the serotonergic system in the mechanism of head twitches induced by be nzodiazepine receptor agonists (BZ-RAs), The HTR induced by BZ-RAs was supp ressed by pretreatment with ketanserine (1 mg/kg, i.p.), a selective 5-HT2 receptor antagonist. Pretreatment with fluoxetine (10 mg/kg, i.p.), a 5-HT reuptake inhibitor, and 8-hydroxy-2-(di-n-propylamino)tetralin, a 5-HT1A re ceptor agonist, also suppressed the HTR induced by BZ-RAs, These results su ggest that the HTR induced by BZ-RAs may be the result of an activation of postsynaptic 5-HT2 receptors, probably due to direct action. Copyright (C) 2001 S. Karger AG, Basel.