Mapping of IP(3)-mediated Ca(2+) signals in single human neuroblastoma SH-SY5Y cells: cell volume shaping the Ca(2+) signal

J Neurophysiol. 2000 Feb;83(2):1052-7. doi: 10.1152/jn.2000.83.2.1052.


Fast confocal laser-scanning microscopy was used to study spatiotemporal properties of IP(3)-mediated Ca(2+) release signals in human SH-SY5Y neuroblastoma cells. [Ca(2+)](i) increases were not affected by ryanodine (30 microgM) or caffeine (10 mM) and largely insensitive to removal of external Ca(2+), indicating predominance of IP(3)-induced Ca(2+) release. Ca(2+) signals evoked by high concentration (10 microM) of the muscarinic agonist carbachol appeared as self-propagating waves initiating in cell processes. At low carbachol concentrations (500 nM) Ca(2+) changes in most cells displayed striking spatiotemporal heterogeneity. The Ca(2+) response in the cell body was delayed and had a smaller amplitude and a slower rise time than that in processes. Ca(2+) changes in processes either occurred in a homogeneous manner throughout the whole process or were sometimes confined to hot spots. Regional differences in surface-to-volume ratio appear to be critical clues that determine the spatiotemporal pattern of intracellular Ca(2+) release signals.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Caffeine / pharmacology
  • Calcium / metabolism
  • Calcium Channels / chemistry
  • Calcium Channels / physiology
  • Calcium Signaling / drug effects
  • Calcium Signaling / physiology*
  • Carbachol / pharmacology
  • Cell Size / physiology
  • Central Nervous System Stimulants / pharmacology
  • Cholinergic Agonists / pharmacology
  • Humans
  • Image Processing, Computer-Assisted
  • Inositol 1,4,5-Trisphosphate / pharmacology*
  • Inositol 1,4,5-Trisphosphate Receptors
  • Microscopy, Confocal
  • Microscopy, Fluorescence
  • Neuroblastoma*
  • Receptors, Cytoplasmic and Nuclear / chemistry
  • Receptors, Cytoplasmic and Nuclear / physiology
  • Tumor Cells, Cultured / chemistry
  • Tumor Cells, Cultured / cytology
  • Tumor Cells, Cultured / physiology


  • Calcium Channels
  • Central Nervous System Stimulants
  • Cholinergic Agonists
  • ITPR1 protein, human
  • Inositol 1,4,5-Trisphosphate Receptors
  • Receptors, Cytoplasmic and Nuclear
  • Caffeine
  • Inositol 1,4,5-Trisphosphate
  • Carbachol
  • Calcium