Membrane Potential Measurements in Cultured Intestinal Villi

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Abstract
Fragmented epithelia of newborn rat small intestine were successfully cultured for periods of up to 4 weeks. Stable intracellular recordings of membrane potential were obtained from these cultured cells. Membrane resting potential varied according to cell location along a villus. The potentials ranged from -70 to -15 mV, being highest at the tip of the villus. The mean resting potential and membrane resistance were -72.4 mV and 8.6 M Ω, respectively. The membrane potential was markedly dependent on the extracellular K+ concentration ([K]0], but not significantly on [Na]0 and [Cl]0-Deprivation of Ca2+ from the surrounding medium depolarized the membrane by 20 mV. When the cells were cooled down to 6°C, membrane potential was reduced by 40 mV. Based on these data, basic mechanisms underlying the resting potential are discussed in connection with cell differentiation or maturation.