Effects of A23187 and Ca2+ on volume- and thiol-stimulated, ouabain-resistant K+C1- fluxes in low K+ fluxes in low K+ sheep erythrocytes.
Ouabain-resistant (OR), C1- -dependent K+ (K+C1-) transport measured by Rb+ influx in isosmotic and anisosmotic media was stimulated by the Ca2+ ionophore A23187 and EGTA (ethylene-glycol-tetracetic acid) in low K+ (LK) but not in high K+ (HK) sheep red cells. Increasing external Ca2+ concentrations, [Ca2+]o, from about 10(-7) to 10(-3)M in presence of A23187 and in absence of EGTA inhibited OR Rb+ influx, in LK red cells osmotically shrunken or swollen as well as treated with the thiol reagent N-ethylmaleimide (NEM). Hence the volume- and the NEM-stimulated K+C1- transport system in LK cells can be experimentally modulated by cellular Ca2+ or other Me2+, which may interact with sites on the K+C1- transporter under the control of membrane sulfhydryl (SH) groups.
D000818:Animals; D000001:Calcimycin / Q000494:pharmacology*; D002118:Calcium / Q000494:pharmacology*; D002712:Chlorides / Q000097:blood*; D004533:Egtazic Acid / Q000494:pharmacology; D004912:Erythrocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D005033:Ethylmaleimide / Q000494:pharmacology*; D007700:Kinetics; D010042:Ouabain / Q000494:pharmacology*; D011188:Potassium / Q000097:blood* / Q000494:pharmacology; D011189:Potassium Chloride / Q000378:metabolism*; D012756:Sheep
D002712:Chlorides; D000001:Calcimycin; D004533:Egtazic Acid; D010042:Ouabain; D011189:Potassium Chloride; D005033:Ethylmaleimide; D011188:Potassium; D002118:Calcium