Extracellular calcium affects the membrane currents of cultured human keratinocytes

Publisher Website
Google Scholar
Abstract
Electrophysiologic properties of cultured human keratinocytes were studied using the patch voltage-clamp technique. Undifferentiated, proliferative keratinocytes grown in low Ca2+ medium had an average resting membrane potential of −24 mV. Voltage-clamp experiments showed that these cells had two membrane ionic currents: a large voltage-independent leak conductance, and a smaller voltage-dependent Cl− current that activated with depolarization. Increasing the extra-cellular Ca2+ concentration from 0.15 to 2 mM resulted in a doubling of the magnitude of the voltage-gated current and a shift in current activation to more negative potentials. Since levels of extracellular Ca2+ can alter the morphology and differentiation state of keratinocytes, the finding of a Ca2+ -activated Cl− current in these cells suggests a role for this conductance in the initiation of differentiation.