Characterization of chloride and cation channels in cultured human keratinocytes

Luis J V Galietta, Virginia Barone, Michele De Luca, Giovanni Romeo

Research output: Contribution to journalArticlepeer-review


Patch-clamp experiments on human cultured keratinocytes revealed the presence of three types of ion channel. The first type was a Cl--selective channel, the current/voltage relationship of which showed outward rectification, the mean conductance at positive and negative membrane potentials being 66 pS and 16 pS respectively. The second type of channel showed almost equal permeability to alkali ions but was impermeable to Cl- and to the large organic cation N-methyl-d-glucamine. Its current/voltage relationship was linear with a mean unitary conductance of 18 pS in symmetrical 140 mmol/l NaCl. Finally, the third type was a large-conductance cation channel, which had in physiological ionic conditions a peculiar rectifying current/voltage relationship, the shape of which was strongly dependent on the concentration of divalent cations on both sides of the membrane. Lowering of Ca2+ and/or Mg2+ on either side of the patch led to a marked increase of the single-channel current. With identical solutions without Ca2+ and Mg2+ on both sides of the patch the current/voltage relationship became ohmic and reached a conductance of 150-200 pS. In addition, channel activity was reversibly affected by changes of the external Ca2+ concentration. In particular, open-channel probability strongly increased at negative membrane potentials when the external Ca2+ was lowered from millimolar to micromolar values. Whole-cell experiments confirm the role of the extracellular Ca2+ as a modulator of the cation conductance.

Original languageEnglish
Pages (from-to)18-25
Number of pages8
JournalPflugers Archiv European Journal of Physiology
Issue number1-2
Publication statusPublished - Mar 1991


  • Cation channels
  • Chloride channels
  • Human keratinocytes
  • Membrane currents
  • Patch-clamp technique

ASJC Scopus subject areas

  • Physiology


Dive into the research topics of 'Characterization of chloride and cation channels in cultured human keratinocytes'. Together they form a unique fingerprint.

Cite this