Membrane potential changes associated with differentiation of enterocytes in the rat intestinal villi in culture

Fragmented villi of the small intestine isolated from newborn rats were maintained in culture for periods of up to 4 weeks. In culture, floating globular villi and adherent villi were distinguished. Intracellular recordings were made from both types of villi. The membrane potential was highest (about ?70 mV) in the cells at the tip of the villus and was lowest (about ?18 mV) in the cells near the crypt region, showing a continuous gradation according to the cell location. The membrane potential in cultured mature enterocytes was due to the contribution of the electrogenic Na⁺ pump as well as to the Ca²⁺-activated K⁺ conductance. Both the components were temperature and metabolic energy dependent. Based on these data, it is suggested that the Ca²⁺ transport mechanism and the electrogenic Na⁺ pump are involved in the process of cell differentiation or maturation of the intestinal epithelia.