title: Intracellular Ca2+ does not activate the SITS-sensitive anion transporter in barnacle muscle.
abstract: By means of the intracellular dialysis technique, we have measured 36Cl efflux from single barnacle muscle fibers and compared the effects of raising intracellular ionized calcium concentration [( Ca2+]i) to the effects of lowering intracellular pH (pHi). Lowering pHi by 1 unit or less resulted in a 20-fold stimulation of 36Cl efflux which occurred relatively rapidly and which could be inhibited by 90-95% by 4-acetamido-4'-isothio-cyanostilbene-2,2'-disulfonic acid (SITS). In contrast, raising [Ca2+]i as much as 250-fold resulted in a relatively small increase of 36Cl efflux. The small increase occurred after a long latency, developed slowly and could not be blocked or prevented by treatment with SITS. We conclude that the increase of the SITS-sensitive 36Cl efflux caused by a fall of pHi is not mediated by a rise of [Ca2+]i.
authors: Department of Physiology and Biophysics, University of Texas Medical Branch, Galveston 77550.
authors: P
authors: P
authors: Matsumoto
authors: J M
authors: JM
authors: Russell
mesh_terms: D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D002132:Calcium Radioisotopes; D002352:Carrier Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D027963:Chloride-Bicarbonate Antiporters; D002713:Chlorine / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008565:Membrane Proteins; D009132:Muscles / Q000187:drug effects / Q000378:metabolism*; D011868:Radioisotopes; D012964:Sodium / Q000378:metabolism / Q000494:pharmacology; D013267:Stilbenes / Q000494:pharmacology*; D001468:Thoracica / Q000378:metabolism*
chemical_list: D002132:Calcium Radioisotopes; D002352:Carrier Proteins; D027963:Chloride-Bicarbonate Antiporters; D008565:Membrane Proteins; D011868:Radioisotopes; D013267:Stilbenes; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; D002713:Chlorine; D012964:Sodium; D002118:Calcium