[Neurotransmitters, neurohormones and prolactin].

After pointing out the reasons for undertaking the study of the regulation of prolactin secretion, the neuroendocrine mechanisms implicated in such secretion are discussed. Special attention is dedicated to the participation of chemical agents. Thus, the principal effects dealt with are: the net inhibition produced by dopamine and the less generalized inhibition effects of nicotine and somatostatin; the facilitatory action of serotoninergic pathways, TRH, histamine and endorphins. The dual effect described for GABA and noradrenaline, as well as some paradoxical actions, e.g., the antiserotoninergic and antihistaminergic H2 drugs which liberate prolactin in basal conditions but abolish the prolactin releasing effect of the respective agonist, or the immediate blocking effect of muscarinic agonists and antagonists are discussed. Finally, the possibility of a new mechanism of control at anterior pituitary receptors level is postulated.