Control of action potential propagation by intracellular Ca2+ in cultured rat dorsal root ganglion cells.
1. To assess the role of intracellular Ca2+ in action potential (AP) propagation, whole-cell recordings of cultured dorsal root ganglion (DRG) cells were carried out while Ca2+ was simultaneously measured with a laser-scanning confocal microscope. 2. Flash photolytic liberation of a Ca2+ buffer during trains of APs which partly failed to invade the DRG cell body immediately lowered intracellular Ca2+ and restored safe AP propagation. Furthermore, the speed of the propagated AP was reduced considerably when intracellular Ca2+ was increased by flash photolysis of caged Ca2+. 3. Both results suggest that intracellular Ca2+ regulates the safety factor for AP propagation and may thus provide a control mechanism for synaptic integration, which acts pre- as well as postsynaptically.
Lüscher
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Department of Physiology, University of Bern, Switzerland. LUESCHERC@pyl.unibe.ch
Lipp
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Lüscher
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Niggli
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D000085:Acetates / Q000494:pharmacology; D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D015220:Calcium Channels / Q000378:metabolism; D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology; D004594:Electrophysiology; D005029:Ethylenediamines / Q000494:pharmacology; D005456:Fluorescent Dyes / Q000378:metabolism; D005727:Ganglia, Spinal / Q000166:cytology / Q000378:metabolism*; D007700:Kinetics; D018613:Microscopy, Confocal; D009431:Neural Conduction; D018408:Patch-Clamp Techniques / Q000379:methods; D010782:Photolysis; D051381:Rats
D000085:Acetates; D015220:Calcium Channels; D002614:Chelating Agents; D005029:Ethylenediamines; D005456:Fluorescent Dyes; C057014:DM-nitrophen; D002118:Calcium