Activation of Ca2+-activated Cl- current by depolarizing steps in rabbit urethral interstitial cells.
Interstitial cells were isolated from strips of rabbit urethra for study using the amphotericin B perforated-patch technique. Depolarizing steps to -30 mV or greater activated a Ca2+ current (ICa), followed by a Ca2+-activated Cl- current, and, on stepping back to -80 mV, large Cl- tail currents were observed. Both currents were abolished when the cells were superfused with Ca2+-free bath solution, suggesting that Ca2+ influx was necessary for activation of the Cl- current. The Cl- current was also abolished when Ba2+ was substituted for Ca2+ in the bath or the cell was dialyzed with EGTA (2 mM). The Cl- current was also reduced by cyclopiazonic acid, ryanodine, 2-aminoethoxydiphenyl borate (2-APB), and xestospongin C, suggesting that Ca2+-induced Ca2+ release (CICR) involving both ryanodine and inositol 1,4,5-trisphosphate receptors contributes to its activation.
Hollywood
M A
MA
Smooth Muscle Group, Department of Physiology, The Queen's University of Belfast, Belfast BT9 7BL, Northern Ireland, UK.
Sergeant
G P
GP
McHale
N G
NG
Thornbury
K D
KD
D000818:Animals; D001464:Barium / Q000494:pharmacology; D001683:Biological Clocks / Q000187:drug effects / Q000502:physiology*; D002118:Calcium / Q000494:pharmacology / Q000502:physiology*; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology; D018118:Chloride Channels / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D005260:Female; D053496:Inositol 1,4,5-Trisphosphate Receptors; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D011817:Rabbits; D018160:Receptors, Cytoplasmic and Nuclear / Q000187:drug effects / Q000378:metabolism; D019837:Ryanodine Receptor Calcium Release Channel / Q000187:drug effects / Q000378:metabolism; D014521:Urethra / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*
D015220:Calcium Channels; D002614:Chelating Agents; D018118:Chloride Channels; D053496:Inositol 1,4,5-Trisphosphate Receptors; D018160:Receptors, Cytoplasmic and Nuclear; D019837:Ryanodine Receptor Calcium Release Channel; D001464:Barium; D002118:Calcium