[The role of calcium and potassium ions in the response of the mouse mammary secretory and myoepithelial cells to treatment with oxytocin].

Experiments were carried out in lactating white mice. Removal of Ca(2+)-ions from the perfusion solution reduced the amplitude and duration of the membrane potential changes in the secretory cells in the mammary gland alveolus. The extra- and intracellular Ca(2+)-ions participate in development of contraction responses of myoepithelial cells. Removal of K(+)-ions from perfusion solution and increase of K(+)-ions concentration in the medium to 20 mmol/l inhibit the development of response of secretory cells to oxytocin action. These changes in K(+)-ions concentration do not affect the contractile response of the myoepithelial cells. The findings suggest that there are essential differences in the participation of Ca(2+)- and K(+)-ions in mechanisms of the mammary secretory and myoepithelial cells responses to oxytocin action.