Intercellular propagation of calcium waves mediated by inositol trisphosphate.
Two types of calcium (Ca2+) signaling-propagating intercellular Ca2+ waves of increasing intracellular Ca2+ concentration ([Ca2+]i) and nonpropagating oscillations in [Ca2+]i-co-exist in a variety of cell types. To investigate this difference in Ca2+ signaling, airway epithelial cells were loaded with heparin, an inositol 1,4,5-triphosphate (IP3) receptor antagonist, by pulsed, high-frequency electroporation. Heparin inhibited propagation of intercellular Ca2+ waves but not oscillations of [Ca2+]i. In heparin-free cells, Ca2+ waves propagated through cells displaying [Ca2+]i oscillations. Depletion of intracellular Ca2+ pools with the Ca2+-pump inhibitor thapsigargin also inhibited the propagation of Ca2+ waves. These studies demonstrate that the release of Ca2+ by IP3 is necessary for the propagation of intercellular Ca2+ waves and suggest that IP3 moves through gap junctions to communicate intercellular Ca2+ waves.
Boitano
S
S
Department of Anatomy, UCLA School of Medicine, CA 90024.
Dirksen
E R
ER
Sanderson
M J
MJ
D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D002809:Chondroitin Sulfates / Q000494:pharmacology; D004558:Electric Stimulation; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D005456:Fluorescent Dyes; D006493:Heparin / Q000494:pharmacology; D015544:Inositol 1,4,5-Trisphosphate / Q000494:pharmacology / Q000502:physiology*; D007365:Intercellular Junctions / Q000502:physiology; D012137:Respiratory System / Q000187:drug effects / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D013729:Terpenes / Q000494:pharmacology; D019284:Thapsigargin
D005456:Fluorescent Dyes; D013729:Terpenes; D019284:Thapsigargin; D015544:Inositol 1,4,5-Trisphosphate; D006493:Heparin; D002809:Chondroitin Sulfates; D002118:Calcium