Possible Interaction: Botulinum Toxins, Type A and Capsaicin

“ BoNT/A reduced blood flow (F1,26 = 109.5, P < 0.001) and skin temperature (F1,26 = 63.1, P < 0.001) at the capsaicin injection sites compared to saline and its suppressive effect was maximal at days 3 and 7 (P < 0.05, post hoc test).”

“However, capsaicin‐induced pain sensation (by a visual analogue scale), flare area (by acetate sheet) and changes in cutaneous blood flow (CBF, by laser Doppler flowmetry) were reduced when capsaicin was administered inside (protocol A) the BoNT/A treated area.”

“Occurrence of cleaved SNAP‐25 in TNC and BoNT/A antinociceptive activity in formalin‐induced orofacial pain were prevented by denervation with capsaicin.”

“ Capsaicin induced contractions were not inhibited by 3-hour incubation but they were significantly inhibited by overnight incubation with 100 nM botulinum neurotoxin A (30% compared to control strips).”

“Subcutaneous administration of BoNT‐A (2.5, 5 and 10 U) reduced plasma extravasation (PE) caused by electrical stimulation of the saphenous nerve or capsaicin in the rat hindpaw skin (ANOVA, Post hoc Tukey, p < 0.05, n = 6).”

“ Capsaicin pretreatment, in vitro, reduced nerve stimulation or KCl-induced uptake of BoNT/A into motor nerve endings and cholinergic Neuro 2a cells.”

“In animals that were pretreated with capsazepine, capsaicin failed to protect against the neuroparalytic effects of BoNT/A. In vivo analyses demonstrated that capsaicin … BoNT/A. The twitch response to nerve stimulation was greater for EDL preparations isolated from mice injected with capsaicin before BoNT/A. Capsaicin … BoNT/A ….”

“RESULTS Pretreatment with 5 U/kg BT -A si gnificantly reduced or completely abolished the enhanced sensitivity to mechanical and thermal stimuli provoked by peripheral carrageenan or cap saicin in jections.”

“Although BTX tended to reverse detrusor overactivity secondary to intravesical capsaicin , this difference was not statistically significant.”

“BTX was more effective in blocking the effect of ATP than of capsaicin, although BTX injection did show a trend in reducing the contraction frequencies and amplitudes induced by capsaicin.”

“Functional effects included dose-related inhibition of capsaicin responses on calcium imaging after acute treatment with botulinum neurotoxins A and E. Conclusion Differential levels of SV2A protein expression in clinical disorders may identify potential new targets for botulinum neurotoxin therapy.”