title: Potassium induced changes in cell volume of gallbladder epithelium.
abstract: The mechanisms of transmembrane K and anion movements were investigated by measurement of the changes in cell volume, apical membrane potential difference, and intracellular K activity resulting from exposure of Necturus gallbladder to solutions with increased K concentration. Cell swelling occurred when the tissue was exposed bilaterally to 25 mmol/l K. This swelling was both Cl and HCO3 dependent, but was not blocked by DIDS or bumetanide. Unilateral tenfold increases in extracellular K concentration did not cause cell swelling; addition of 5 mmol/l Ba to the contralateral cell surface resulted in cell volume increases comparable to those seen with bilateral K increase. Complete blockage of K channels by Ba could be demonstrated electrophysiologically at normal extracellular K concentrations but not in the presence of increased K. Our results were consistent with the passive movement of K through Ba-sensitive channels in both cell membranes. We were unable to detect other mechanisms for transmembrane K movement. The cell swelling caused by exposure to 25 mmol/l K was not due to intracellular K accumulation and may be related to the effects of membrane depolarization on voltage sensitive anion transport processes.
mesh_terms: D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D000873:Anthracenes / Q000494:pharmacology; D001464:Barium / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D002034:Bumetanide / Q000494:pharmacology; D002712:Chlorides / Q000378:metabolism; D005704:Gallbladder / Q000166:cytology* / Q000187:drug effects; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects; D008564:Membrane Potentials / Q000187:drug effects; D009338:Necturus maculosus; D011188:Potassium / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D000873:Anthracenes; D002712:Chlorides; D007473:Ion Channels; D002034:Bumetanide; D001464:Barium; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; C010030:9-anthroic acid; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D011188:Potassium