title: Sensitivity of embryonic rat dorsal root ganglia neurons to Clostridium botulinum neurotoxins.
abstract: 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.
authors.affiliation: Centre for Applied Microbiology and Research, Salisbury, Wiltshire, UK.
authors.forename: M J
authors.initials: MJ
authors.lastname: Welch
authors.forename: J R
authors.initials: JR
authors.lastname: Purkiss
authors.forename: K A
authors.initials: KA
authors.lastname: Foster
mesh_terms: D000818:Animals; D001905:Botulinum Toxins / Q000633:toxicity*; D002118:Calcium / Q000502:physiology; D002478:Cells, Cultured; D005727:Ganglia, Spinal / Q000187:drug effects* / Q000196:embryology; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013373:Substance P / Q000378:metabolism
chemical_list: D013373:Substance P; D001905:Botulinum Toxins; D011188:Potassium; D002118:Calcium