BRAIN AND SERUM CALCIUM CONCENTRATIONS FOLLOWING ELECTROCONVULSIVE SHOCK OR BICUCULLINE‐INDUCED CONVULSIONS IN RATS

1 A single electroconvulsive shock (ECS; 125 V, 1 s, 50 Hz) given to rats anaesthetized with halothane produced little change in either serum or regional brain calcium concentrations, compared to rats anaesthetized with halothane, either 5 min or 24 h after the convulsion. Both anaesthetic and ECS‐treated rats showed an elevated serum concentration 5 min after the ECS. 2 When 5 ECS were given spread out over 10 days there were no significant calcium concentration changes in either serum or brain except for an increase in the pons/medulla. 3 A single convulsion produced by bicuculline (0.375 mg/kg i.v.) resulted in a marked increase in the calcium concentration in serum, but not brain, 5 min later. Diazepam pretreatment (10 mg/kg i.v.) prevented both the convulsion and the serum calcium change. 4 Results are discussed in relation to clinical data on calcium changes following electroconvulsive therapy (ECT) and the enhanced monoamine‐mediated behaviours which follow ECS administration to rats.