Quinine inhibits multiple Na+ and K+ transport mechanisms in Ehrlich ascites tumor cells.
The interaction of quinine with K+ and Na+ transport mechanisms has been investigated in Ehrlich ascites tumor cells. Quinine affects both Ca2+-dependent K+ channel and total K+ influx. Activation of Ca+-dependent K+ channels by propranolol is abolished by quinine (1 mM). In addition, quinine inhibits the ouabain-sensitive component of K+ influx with an apparent Ki of 0.32 +/- 0.02 mM and the furosemide-sensitive component with a Ki of 0.24 +/- 0.01 mM. Furthermore, a significant fraction (52%) of Na+ influx is inhibited by quinine. The same component is sensitive to amiloride, suggesting that it represents Na+/H+ antiport. Concomitant with the inhibition of K+ and Na+ transport, quinine stimulates ATP hydrolysis by 57%. The results suggest that quinine exerts broad, nonspecific effects on cellular mechanisms which serve to regulate cation transport in Ehrlich cells.
Smith
T C
TC
Department of Physiology, University of Texas Health Science Center, San Antonio 78284-7756.
Levinson
C
C
D000255:Adenosine Triphosphate / Q000378:metabolism; D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000494:pharmacology; D002286:Carcinoma, Ehrlich Tumor / Q000378:metabolism*; D005665:Furosemide / Q000494:pharmacology; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D008813:Mice, Inbred ICR; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism*; D015221:Potassium Channels / Q000187:drug effects / Q000378:metabolism; D011433:Propranolol / Q000494:pharmacology; D011803:Quinine / Q000494:pharmacology*; D012964:Sodium / Q000378:metabolism*
D015221:Potassium Channels; D010042:Ouabain; D000584:Amiloride; D005665:Furosemide; D000255:Adenosine Triphosphate; D012964:Sodium; D011433:Propranolol; D011803:Quinine; D011188:Potassium; D002118:Calcium