Electroconvulsive shock and postsynaptic catecholamine effects: Increased psychomotor stimulant action of apomorphine and clonidine in reserpine pretreated mice by repeated ECS

Summary

Male mice were administered electric convulsive shocks (ECS) once daily for one (ECS×I), three (ECS×III) or seven days (ECS×VII). One (day 1), three (day 3) or six days (day 6) later they received reserpine 10 mg/ kg, followed 2 hours later by clonidine, 1.5 mg/kg, and/or apomorphine, 1.5 mg/kg. Control animals received the same drug treatments but no ECS. The motor activity was recorded for 1 hour, starting immediately after the last drug injection. The behavioural depression induced by reserpine was equally pronounced in ECS-pretreated animals as in the control animals. The psychomotor stimulant effects of clonidine and/or apomorphine, given after reserpine was, however, enhanced by pretreatment with ECS×VII, day 1. Pretreatment with ECS×VII increased the motor activity also in animals given reserpine, apomorphine and clonidine at day 3 or day 6. ECS×III was also effective in this respect at day 1, whereas ECS×I, day 1, was ineffective. Mice given ECS×VII but no drug treatment showed at day 1 an increased motor activity during the initial 10 min and a decreased activity during the last 10 min of the 1 hour recording period. At day 3 and day 6 after ECS×VII the motor activity was increased in comparison to that in untreated control animals during the whole 1 hour period. Animals given repeated ECS furthermore showed increased irritability and reduced body weight.

The results indicate that repeated ECS increase the sensitivity of post-synaptic catecholamine receptors in the brain or alter neuronal structures which are connected to these receptors.