Prolactin response to electroconvulsive shock in anesthetized rats.

Serum prolactin level (SPL) of anesthetized rats was measured in response to electroconvulsive shock (ECS). This measurement served as an indicator of dopaminergic and serotonergic activity. Such neurotransmitter activity was modulated by pretreatment with cyproheptadine, parachlorophenylalanine (PCPA), pimozide, bromocriptine or L-dopa. A statistically significant lowered SPL was found in rats given ECS plus antiserotonergic agents, in comparison with animals receiving antiserotonergic agent or ECS alone. When ECS was administered to rats pretreated with the dopaminergic blocker, pimozide, there was a significant decrease in SPL, compared with animals receiving pimozide alone. When the dopaminergic system was stimulated by dopamine agonists, there was no elevation of SPL in response to ECS. Thus, there may be a balance between serotonergic and dopaminergic systems. The agents used in the experiment may upset this balance and produce a change in prolactin response to a given ECT stimulus.