Toxin sensitivity of the calcium-dependent rubidium efflux in Madin-Darby canine kidney cells.
86Rb+ efflux was measured on polarized Madin-Darby canine kidney cells under A23187 or ATP stimulation. This efflux, inhibited by barium, Leiurus quinquestriatus hebraeus venom and charybdotoxin was attributed to the stimulation of Ca(++)-activated maxi K+ channels. Snake venom from Dendroaspis polylepis did not alter the stimulation as well as did apamine. ATP was effective on both the apical and basolateral membranes and the Ca(++)-activated maxi K+ channels were predominantly found on the basolateral membrane. This study presents the physiological evidence that dendrotoxin is ineffective on the epithelial Ca(++)-activated maxi K+ channel present in MDCK cells.
Tauc
M
M
Département de Biologie Cellulaire et Moléculaire, CEN Saclay, Gif sur Yvette, France.
Gastineau
M
M
Poujeol
P
P
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D001464:Barium / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology*; D002460:Cell Line; D018999:Charybdotoxin; D004285:Dogs; D007668:Kidney / Q000378:metabolism*; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D012413:Rubidium / Q000378:metabolism*; D012414:Rubidium Radioisotopes; D012604:Scorpion Venoms / Q000494:pharmacology; D014118:Toxins, Biological / Q000494:pharmacology*
D015221:Potassium Channels; D012414:Rubidium Radioisotopes; D012604:Scorpion Venoms; D014118:Toxins, Biological; D018999:Charybdotoxin; D001464:Barium; D000001:Calcimycin; D000255:Adenosine Triphosphate; D012413:Rubidium; D002118:Calcium