[The stimulation of prolactin secretion by the simultaneous inhibition of the dopaminergic and activation of the serotoninergic systems in the hypothalamus].

Lactotropic adenohypophyseal function and lactation intensity were studied under simultaneous blockade of dopamine receptors and stimulation of serotonin metabolism in the rat hypothalamus. Blockade of hypothalamic dopamine receptors by tricedil decreased the dopamine level, increased the serotonin content and intensified its metabolism thus increasing the prolactin secretion. Under these conditions, tryptophan application potentiated the above changes in hypothalamic catecholamine and indolamine metabolism, increased the prolactin secretion. The latter is associated with the brain serotoninergic system reactivity to suckling impulses: an important factor in the lactation reflex. Tryptophan maintains a high level of hypothalamic serotonin metabolism, maintaining an increase in the prolactin secretion level and secretory activity of the mammary glands.