Activation of red cell Ca2(+)-activated K+ channel by Ca2+ involves a temperature-dependent step.
We found that vanadate-induced 45Ca2+ uptake by red cells is maximal at 25 degrees C. At this temperature, the Cai-induced increase of the K+ permeability (the Gárdos effect) shows a lag (up to 8 min) which is not observed at 37 degrees C. This cannot be explained by the lack of availability of Ca2+ for the Ca2(+)-activated K+ channel, and suggests that its activation by Ca2+ is mediated by a temperature-dependent mechanism which remains unknown so far. The lag is not observed when the Gárdos effect was initiated by propranolol. This shows that the putative temperature-dependent step is different from chloride transport.
Varecka
L
L
Mental Health Research Center of the Medical Bionics Institute, Psychiatric Hospital, Pezinok, Czechoslovakia.
Peterajová
E
E
D001693:Biological Transport, Active / Q000187:drug effects; D002118:Calcium / Q000097:blood* / Q000494:pharmacology; D004912:Erythrocytes / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D007700:Kinetics; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D011433:Propranolol / Q000494:pharmacology; D013696:Temperature; D014638:Vanadates / Q000494:pharmacology
D015221:Potassium Channels; D014638:Vanadates; D011433:Propranolol; D002118:Calcium