Reversal by EGTA of the enhanced secretory responsiveness of mast cells due to treatment with ouabain.
The effect of EGTA on the enhancement by ouabain of compound 48/80-induced secretion from mast cells was compared with the effect on the Na(+)-K+ pump activity. The time-dependent secretory enhancement by ouabain was blocked by addition of EGTA to the cell suspension concomitantly with the addition of ouabain, and EGTA caused a large increase in the pump activity. Addition of 10 microM EGTA to ouabain-treated cells stopped but did not reverse the enhancement. The experiments show that the effect of ouabain was due to changes in a calcium pool utilized in compound 48/80-induced secretion following changes in the Na+,K+ pump activity.
Johansen
T
T
Department of Pharmacology, Medical School, Odense University, Denmark.
Knudsen
T
T
Bertelsen
H
H
D000818:Animals; D001692:Biological Transport; D004305:Dose-Response Relationship, Drug; D004533:Egtazic Acid / Q000494:pharmacology*; D008297:Male; D008407:Mast Cells / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D010042:Ouabain / Q000008:administration & dosage / Q000494:pharmacology*; D011188:Potassium / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012414:Rubidium Radioisotopes; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D012414:Rubidium Radioisotopes; D004533:Egtazic Acid; D010042:Ouabain; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium