Sensitivity of embryonic rat dorsal root ganglia neurons to Clostridium botulinum neurotoxins

Toxicon. 2000 Feb;38(2):245-58. doi: 10.1016/s0041-0101(99)00153-1.


Clostridium botulinum neurotoxins (BoNT) are zinc dependent endopeptidases which, once internalised into the neuronal cytosol, block neurotransmission by proteolysis of membrane-associated proteins putatively involved in synaptic vesicle docking and fusion with the plasma membrane. Although many studies have used a variety of cellular systems to study the neurotoxins, most require relatively large amounts of toxin or permeabilisation to internalise the neurotoxin. We present here a primary culture of embryonic rat dorsal root ganglia (DRG) neurons that exhibits calcium-dependent substance P secretion when depolarised with elevated extracellular potassium and is naturally BoNT sensitive. The DRG neurons showed a different IC50 for each of the toxins tested with a 1000 fold difference between the most and least potent neurotoxins (0.05, 0.3, 30 and approximately 60 nM for A, C, F and B, respectively). BoNT/A cleavage of SNAP-25 was seen as early as 2 h, but substance P secretion was not significantly inhibited until 4 h intoxication and the effects of BoNT/A were observed for as long as 15 days. This primary neuronal culture system represents a new and sensitive cellular model for the in vitro study of the botulinum neurotoxins.

MeSH terms

  • Animals
  • Botulinum Toxins / toxicity*
  • Calcium / physiology
  • Cells, Cultured
  • Ganglia, Spinal / drug effects*
  • Ganglia, Spinal / embryology
  • Potassium / pharmacology
  • Rats
  • Rats, Sprague-Dawley
  • Substance P / metabolism


  • Substance P
  • Botulinum Toxins
  • Potassium
  • Calcium