Ca2+ channel blockers inhibit secretory C1-channels in intestinal epithelial cells.
Outwardly rectifying Cl- channels are present in the human colonic cell line (HT29D4). The classical Cl- channel blocker 5-nitro-2(3-phenylpropylamino)benzoate inhibits Cl- channel activity with a K0.5 value of 20 microM. Epithelial Cl- channel activity is inhibited by Ca2+ channel blockers. Phenylalkylamines are the most effective inhibitors. (+/-)Verapamil and (-)desmethoxyverapamil induce flickering and then the complete blockade of Cl- channels recorded from outside-out patches. K0.5 values are 60 microM and 100 microM for (-)desmethoxyverapamil and (+/-)verapamil, respectively. Other classes of L-type Ca2+ channel blockers have also been studied but they are less active.
Champigny
G
G
Institut de Pharacologie moléculaire et cellulaire, Valbonne, France.
Verrier
B
B
Lazdunski
M
M
D000230:Adenocarcinoma; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D002460:Cell Line; D018118:Chloride Channels; D003110:Colonic Neoplasms; D006801:Humans; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology*; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D008565:Membrane Proteins / Q000502:physiology*
D002121:Calcium Channel Blockers; D018118:Chloride Channels; D007473:Ion Channels; D008565:Membrane Proteins