Inhibition of red cell Ca2+-dependent K+ channels by snake venoms.
We have investigated the effects of several snake venoms on the Ca2+-dependent K+ channels of human red cells. A heat-resistant component of the venom of the snake Notechis scutatus irreversibly inhibited Ca2+-dependent K+ transport with a Ki value of 0.1-0.2 micrograms/ml. Metabolic changes of the cells modified the maximal effect of the venom. Binding of the venom required extracellular Ca2+ and was quick, but development of full inhibition required additional time. The effects of the venoms from Notechis scutatus and Leiurus quinquestriatus were additive, suggesting that both venoms act through different mechanisms. Venoms of the snakes Vipera russelli russelli and Oxyuranus scutellatus also inhibited Ca2+-dependent K+ transport with the same characteristics as the Notechis scutatus venom.
Alvarez
J
J
Departamento de Bioquímica y Biología Molecular y Fisiología, Facultad de Medicina, Universidad de Valladolid, Spain.
García-Sancho
J
J
D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004912:Erythrocytes / Q000378:metabolism*; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D007555:Isoxazoles / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects; D009504:Neutrophils / Q000378:metabolism; D011188:Potassium / Q000378:metabolism; D015221:Potassium Channels / Q000187:drug effects*; D012910:Snake Venoms / Q000494:pharmacology*; D012964:Sodium / Q000378:metabolism
D007555:Isoxazoles; D015221:Potassium Channels; D012910:Snake Venoms; C013633:oxonol V; D012964:Sodium; D011188:Potassium; D002118:Calcium