The gating of human red cell Ca2(+)-activated K(+)-channels is strongly affected by the permeant cation species.
Using inside-out patches, the effect of various permeant cations on the gating behaviour of the human red cell Ca2(+)-activated K(+)-channel was examined. For symmetric solutions the dwell time histograms indicated two shut and two open states. Mean open times as well as the open-state probability were affected by the permeant cation species: Rb+ stabilised the channel in the open configuration, whereas NH4+ had a destabilising effect. Intermediate stability was obtained in K+ solutions. Bi-ionic experiments indicated that the gating was influenced by the ion species occupying the channel, rather than by ions bound to external modifier sites.
Bennekou
P
P
August Krogh Institute, Copenhagen, Denmark.
Christophersen
P
P
D000641:Ammonia / Q000494:pharmacology*; D002118:Calcium / Q000494:pharmacology; D002414:Cations, Monovalent; D004912:Erythrocytes / Q000502:physiology*; D006801:Humans; D015640:Ion Channel Gating / Q000187:drug effects*; D007700:Kinetics; D011188:Potassium / Q000494:pharmacology*; D015221:Potassium Channels / Q000502:physiology*; D012413:Rubidium / Q000494:pharmacology*
D002414:Cations, Monovalent; D015221:Potassium Channels; D000641:Ammonia; D012413:Rubidium; D011188:Potassium; D002118:Calcium