Enhancement of conductive anion permeability in cultured cells by cetiedil.
Cetiedil, a drug that is reported to block K+-channels, substantially increases the conductive C1- permeability of Chinese hamster ovary (CHO) cells. The permeability was monitored by volume changes in cells treated with gramicidin to increase the cation permeability. Under this circumstance, increases in Cl- conductances result in volume changes detectable by electronic sizing, with the direction determined by the gradients of the permeating ions. In NaCl or KCl media, swelling occurs, but in N-methylglucamine chloride, shrinking. The increases in Cl- conductance could also be measured as an increased 36Cl- flux or by changes in membrane potential (measured by fluorescence of a potential-sensitive dye) toward the Cl- equilibrium potential. The effect of cetiedil was concentration dependent, with maximal effect at 50 microM. The anion specificity for the conductance was NO3- greater than Cl- = Br- much greater than SO4-2 or isethionate. A number of other drugs that influence transport activities had no effect on Cl- conductance. The cetiedil effect on Cl- conductance was observed in one other cell line, but was absent in several other cell types. The cetiedil-induced Cl- conductance in CHO cells appears to involve a different pathway than that induced by exposure to hypotonic medium.
D000818:Animals; D000838:Anions / Q000378:metabolism*; D001381:Azepines / Q000494:pharmacology*; D002460:Cell Line; D002463:Cell Membrane Permeability / Q000187:drug effects*; D002712:Chlorides / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D005260:Female; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism*; D006096:Gramicidin / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D010053:Ovary; D011188:Potassium / Q000378:metabolism; D012964:Sodium / Q000378:metabolism
D000838:Anions; D001381:Azepines; D002712:Chlorides; D006096:Gramicidin; C006955:cetiedil; D012964:Sodium; D011188:Potassium