Calcium ionophore plus excision induce a large conductance chloride channel in membrane patches of human colon carcinoma cells HT-29cl.19A

Experientia. 1993 Apr 15;49(4):313-6. doi: 10.1007/BF01923409.


In excised inside-out membrane patches of the human colon carcinoma HT-29cl.19A cells a large conductance (373 +/- 10 pS) chloride channel was found. Channel activity could only be observed after excision of patches from cells incubated with calcium ionophore. The channel was never observed in cell-attached patches. The channel was strongly voltage dependent, being open only between +30 and -30 mV clamp potentials. The selectivity sequence among anions, deduced from reversal potentials, was I > Br > Cl > F > gluconate. The PNa/PCl was 0.09. Although a similar type of channel has been described earlier, this is the first report stating its appearance in patches of intestinal epithelial cells requiring the combined action of Ca2+ ionophore and excision, suggesting its control by an intracellular compound.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calcimycin / pharmacology*
  • Calcium / metabolism
  • Chloride Channels
  • Colonic Neoplasms / metabolism
  • Epithelium / metabolism
  • Humans
  • Intestinal Mucosa / metabolism*
  • Membrane Potentials / drug effects
  • Membrane Proteins / drug effects*
  • Membrane Proteins / physiology
  • Tumor Cells, Cultured


  • Chloride Channels
  • Membrane Proteins
  • Calcimycin
  • Calcium