Intracellular calcium increases in growth cones exposed to tetracaine

Anesth Analg. 2004 Mar;98(3):841-5, table of contents. doi: 10.1213/01.ane.0000099718.51681.55.


Neurotoxicity of local anesthetics has been reported for both matured and growing neurons. In the present study, we examined if tetracaine increases Ca(2+) concentration during growth cone collapse. Intracellular Ca(2+) concentration was measured by fura 2/AM after exposure to tetracaine. Tetracaine (1-2 mM) induced increases in intra-growth cone Ca(2+) concentration (P < 0.01). The Ca(2+) hot spot was expanded into the neurite from the periphery towards the cell body. When tetracaine was applied to growth cones in Ca(2+) free media, the increase was minor. However, tetracaine induced growth cone collapse even in the culture media, which did not contain Ca(2+). Ni(2+) (100 microM; a general Ca(2+) channel inhibitor) and BAPTA-AM (5 microM; intracellular Ca(2+) chelator) could not inhibit growth cone collapse induced by 1-2 mM tetracaine. Tetracaine (>1 mM) induces collapse and Ca(2+) increase at growth cones simultaneously; however, these two phenomena might be provoked independently.

Implications: Tetracaine induced intracellular Ca(2+) increases and growth cone collapse in dorsal root ganglion neurons. The Ca(2+) hot spot in the growth cone expanded into the neurite from periphery towards the cell body.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anesthetics, Local / pharmacology*
  • Animals
  • Calcium / metabolism*
  • Calcium / physiology
  • Calcium Channel Blockers / pharmacology
  • Cell Membrane / metabolism
  • Chelating Agents / pharmacology
  • Chick Embryo
  • Culture Media
  • Fluorescent Dyes
  • Fura-2
  • Ganglia, Spinal / cytology
  • Ganglia, Spinal / drug effects
  • Ganglia, Spinal / embryology
  • Growth Cones / metabolism*
  • Growth Cones / ultrastructure
  • Neurites / drug effects
  • Neurites / ultrastructure
  • Tetracaine / pharmacology*


  • Anesthetics, Local
  • Calcium Channel Blockers
  • Chelating Agents
  • Culture Media
  • Fluorescent Dyes
  • Tetracaine
  • Calcium
  • Fura-2