Leiurus quinquestriatus venom inhibits different kinds of Ca2+-dependent K+ channels.
A minor protein component of Leiurus quinquestriatus venom has been reported to inhibit selectively the apamin-insensitive Ca2+-dependent K+ channels of mammalian skeletal muscle (Miller, C., Moczydlowski, E., Latorre, R. and Phillips, M. (1985) Nature 313, 316-318). We report the effect of the venom on both the apamin-insensitive channels of the human erythrocyte, the Ehrlich cell and the rat thymocyte and the apamin-sensitive channel of the guinea pig hepatocyte. The venom inhibited Ca2+-dependent K+ transport in all the cases with a Ki value within the range of 1 to 10 micrograms/ml, similar to that reported previously in muscle. Valinomycin-induced K+ transport was also antagonized by the venom but its sensitivity was about 1/10 as much as that of the Ca2+-dependent K+ channel.
Abia
A
A
Lobatón
C D
CD
Moreno
A
A
García-Sancho
J
J
D001030:Apamin / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology*; D004229:Dithiothreitol / Q000494:pharmacology; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology*; D007700:Kinetics; D011188:Potassium / Q000097:blood*; D012604:Scorpion Venoms / Q000494:pharmacology*
D007473:Ion Channels; D012604:Scorpion Venoms; D001030:Apamin; D011188:Potassium; D002118:Calcium; D004229:Dithiothreitol