Effect of single and repeated electroconvulsive shock on serotonergic system in rat brain—II behavioural studies

Effect of single and repeated (once daily, for 10 days) ECS (150 V, 0.4 sec) on head twitch behaviour (HTB) induced by 5-HT (i.v.t.) or 5-HTP (i.p.) in tranylcypromine-treated rats was investigated. Single ECS did not change the frequency of head twitch evoked by both serotonergic agents at any time studied (1, 24 and 48 hr). Repeated ECS, having no effect at 1 hr, increased significantly the frequency of head twitch induced by both 5-HT (i.v.t.) and 5-HTP (i.p.) by approximately 100% at 24 and 48 hr after the last shock. It is concluded that repeated ECS increases the sensitivity of central 5-HT receptors.