[Ionic dependence of hyperpolarized changes of the membrane potential of breast secretory cells]

In lactating albino mice, an augmentation of the membrane potential of secretory cells and of transepithelial potential difference caused by oxytocin and acetylcholine, was shown to be accompanied by the fall of transepithelial electrical impedance. The calcium-dependent increase of the permeability of plasmatic membrane for K+ seems to be the main cause of the above responses.