[Reactions of the secretory and myoepithelial cells of mammary alveoli to neuromediators and oxytocin].

The hyperpolarization of the secretory cells MP and the alveolar myoepithelium contraction in response to oxytocin depend to a greater extent on the accompanying effects of catecholamines as compared with acetylcholine. The hyperpolarization of the secretory cells MP induced with oxytocin and acetylcholine diminishes in its amplitude and duration in presence of colchicine (25 microM). Rhythmic hyperpolarization changes of the MP induced with 1-minute action of oxytocin and acetylcholine coincide in time with the exocytosis period of secretory vesicles and the beginning of new biosynthesis.