Radial localization of inositol 1,4,5-trisphosphate-sensitive Ca2+ release sites in Xenopus oocytes resolved by axial confocal linescan imaging

被引:42
作者
Callamaras, N [1 ]
Parker, I [1 ]
机构
[1] Univ Calif Irvine, Dept Psychobiol, Cellular & Mol Neurobiol Lab, Irvine, CA 92697 USA
关键词
calcium; inositol trisphosphate; oocyte; confocal microscopy;
D O I
10.1085/jgp.113.2.199
中图分类号
Q4 [生理学];
学科分类号
071003 ;
摘要
The radial localization and properties of elementary calcium release events ("puffs") were studied in Xenopus oocytes using a confocal microscope equipped with a piezoelectric focussing unit to allow rapid (>100 Hz) imaging of calcium signals along a radial line into the cell with a spatial resolution of <0.7 mu m. Weak photorelease of caged inositol 1,4,5-trisphosphate (InsP(3)) evoked puffs arising predominantly within a 6-mu m thick band located within a few micrometers of the cell surface. Approximately 25% of puffs had a restricted radial spread, consistent with calcium release from a single site. Most puffs, however, exhibited a greater radial spread (3.25 mu m), likely involving recruitment of radially neighboring release sites. Calcium waves evoked by just suprathreshold stimuli exhibited radial calcium distributions consistent with inward diffusion of calcium liberated at puff sites, whereas stronger flashes evoked strong, short-latency signals at depths inward from puff sites, indicating deep InsP(3)-sensitive stores activated at higher concentrations of InsP(3). Immunolocalization of InsP(3) receptors showed punctate staining throughout a region corresponding to the localization of puffs and subplasmalemmal endoplasmic reticulum. The radial organization of puff sites a few micrometers inward from the plasma membrane may have important consequences for activation of calcium-dependent ion channels and "capacitative" calcium influx. However, on the macroscopic (hundreds of micrometers) scale of global calcium waves, release can be considered to occur primarily within a thin, essentially two-dimensional subplasmalemmal shell.
引用
收藏
页码:199 / 213
页数:15
相关论文
共 47 条
  • [41] EMPTYING OF INTRACELLULAR CA2+ STORES RELEASES A NOVEL SMALL MESSENGER THAT STIMULATES CA2+ INFLUX
    RANDRIAMAMPITA, C
    TSIEN, RY
    [J]. NATURE, 1993, 364 (6440) : 809 - 814
  • [42] LOCAL CA2+ TRANSIENTS (CA2+ SPARKS) ORIGINATE AT TRANSVERSE TUBULES IN RAT-HEART CELLS
    SHACKLOCK, PS
    WIER, WG
    BALKE, CW
    [J]. JOURNAL OF PHYSIOLOGY-LONDON, 1995, 487 (03): : 601 - 608
  • [43] A continuum of InsP3-mediated elementary Ca2+ signalling events in Xenopus oocytes
    Sun, XP
    Callamaras, N
    Marchant, JS
    Parker, I
    [J]. JOURNAL OF PHYSIOLOGY-LONDON, 1998, 509 (01): : 67 - 80
  • [44] CALCIUM WAVES IN MAMMALIAN HEART - QUANTIFICATION OF ORIGIN, MAGNITUDE, WAVE-FORM, AND VELOCITY
    TAKAMATSU, T
    WIER, WG
    [J]. FASEB JOURNAL, 1990, 4 (05) : 1519 - 1525
  • [45] TERASAKI M, 1993, METHOD CELL BIOL, V38, P211
  • [46] QUANTAL PUFFS OF INTRACELLULAR CA2+ EVOKED BY INOSITOL TRISPHOSPHATE IN XENOPUS OOCYTES
    YAO, Y
    CHOI, J
    PARKER, I
    [J]. JOURNAL OF PHYSIOLOGY-LONDON, 1995, 482 (03): : 533 - 553
  • [47] Zang W. J., 1997, Biophysical Journal, V72, pA342