Extracellular calcium affects the membrane currents of cultured human keratinocytes
✍ Scribed by Theodora M. Mauro; Pamela A. Pappone; R. Rivkah Isseroff
- Publisher
- John Wiley and Sons
- Year
- 1990
- Tongue
- English
- Weight
- 932 KB
- Volume
- 143
- Category
- Article
- ISSN
- 0021-9541
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✦ Synopsis
Abstract
Electrophysiologic properties of cultured human keratinocytes were studied using the patch voltage‐clamp technique. Undifferentiated, proliferative keratinocytes grown in low Ca^2+^ 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 Ca^2+^ 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 Ca^2+^ can alter the morphology and differentiation state of keratinocytes, the finding of a Ca^2+^ ‐activated Cl^−^ current in these cells suggests a role for this conductance in the initiation of differentiation.