Possible role of the serotonergic system in the behavioral effect of massed electroconvulsive shock in rat

Massed electroconvulsive shock (ECS) inhibited escape in a one-way avoidance system and tolerance to this effect developed in rats shocked for 4 consecutive days (1, 4, 5 and 10 ECS respectively). Chronic treatment with p-bromo-N-methylamphetamine (V-III) as well as pretreatment with pCPA antagonized the behavioral disturbing effect of massed ECS strongly supporting the idea that 5-HT plays an important role in observed behavioral effects.