Rapid increase in plasma membrane chloride permeability during wound resealing in starfish oocytes.
Plasma membrane wound repair is an important but poorly understood process. We used femtosecond pulses from a Ti-Sapphire laser to make multiphoton excitation-induced disruptions of the plasma membrane while monitoring the membrane potential and resistance. We observed two types of wounds that depolarized the plasma membrane. At threshold light levels, the membrane potential and resistance returned to prewound values within seconds; these wounds were not easily observed by light microscopy and resealed in the absence of extracellular Ca(2+). Higher light intensities create wounds that are easily visible by light microscopy and require extracellular Ca(2+) to reseal. Within a few seconds the membrane resistance is approximately 100-fold lower, while the membrane potential has depolarized from -80 to -30 mV and is now sensitive to the Cl(-) concentration but not to that of Na(+), K(+), or H(+). We suggest that the chloride sensitivity of the membrane potential, after wound resealing, is due to the fusion of chloride-permeable intracellular membranes with the plasma membrane.
Fein
Alan
A
Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06030, USA. afein@neuron.uchc.edu
Terasaki
Mark
M
D000818:Animals; D000838:Anions; D002122:Calcium Chloride / Q000494:pharmacology; D002413:Cations, Divalent; D002462:Cell Membrane / Q000378:metabolism / Q000528:radiation effects; D002463:Cell Membrane Permeability / Q000187:drug effects / Q000528:radiation effects; D002712:Chlorides / Q000378:metabolism*; D066298:In Vitro Techniques; D007425:Intracellular Membranes / Q000378:metabolism; D017136:Ion Transport; D007834:Lasers; D008561:Membrane Fusion; D008564:Membrane Potentials / Q000187:drug effects / Q000528:radiation effects; D009865:Oocytes / Q000378:metabolism* / Q000473:pathology / Q000528:radiation effects; D018408:Patch-Clamp Techniques; D013215:Starfish; D014817:Vitelline Membrane / Q000528:radiation effects
D000838:Anions; D002413:Cations, Divalent; D002712:Chlorides; D002122:Calcium Chloride