Blockade of the postictal prolactin surge by methysergide

Role of serotonin3 receptors in prolactin release induced by electroconvulsive therapy: a study with ondansetron

The effect of pretreatment with odansetron on prolactin (PRL) release induced by electroconvulsive therapy (ECT) was examined in 16 depressive patients in a double-blind, placebo-controlled crossover study. Ten patients were pretreated with 4 mg and the other six with 8 mg of ondansetron. The order of administration of study medication (ondansetron and placebo) was counterbalanced. The failure of ondansetron to attenuate ECT-induced PRL release suggested that serotonin3 receptors are not involved in mediating this response.

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.

Prolactin and thyrotropin responses to ECT after pindolol administration. A placebo controlled study

The effect of pindolol, a beta-receptor blocker with potent 5-HT1 receptor antagonistic properties, on the prolactin (PRL) and thyrotropin (TSH) responses to electroconvulsive therapy (ECT) was systematically studied in 12 female depressed patients. In a balanced order, crossover design, the patients were given placebo or pindolol 5 mg orally, 1 h prior to bilateral ECT. The last five patients were additionally tested with 10 mg pindolol during the third ECT. Plasma levels of PRL and TSH increased in all three trials, but no consistent effect of pindolol on these hormonal responses could be demonstrated. Pindolol tended to attenuate seizure duration, especially at the 10 mg dose. The participation of 5-HT1 receptor activity in the secretion of PRL and TSH during ECT remains uncertain.

Ritanserin, a 5-HT2 receptor antagonist, does not modify ECT-induced prolactin release

The effect of pretreatment with ritanserin, a potent and selective serotonin-S2 (5-HT2) receptor antagonist, on the prolactin (PRL) response to electroconvulsive therapy (ECT) was studied in seven female patients suffering from major depressive disorder. They were given either ECT alone, or ECT after 10 or 20 mg ritanserin PO, and PRL was estimated in blood samples taken at times -5, 0, +5, +15, +30 and +60 min. The PRL responses after drug administration were not different from the responses after ECT alone. We conclude that, if serotonergic mechanisms are involved in the ECT-induced PRL increase, this neuroendocrine response seems to be rather a 5-HT1 than 5-HT2 receptor mediated event.