Botulinum Toxin type A reduces capsaicin-evoked pain and neurogenic vasodilatation in human skin

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• 作者：Valeria Tugnoli ; Jay Guido Capone ; Roberto Eleopra ; Rocco Quatrale ; Mariachiara Sensi ; Ernesto Gastaldo ; Maria Rosaria Tola ; Pierangelo Geppetti
• 关键词：Botulinum toxin ; Capsaicin ; Neurogenic inflammation ; Pain
• 刊名：Pain
• 出版年：2007
• 出版时间：July 2007
• 年：2007
• 卷：130
• 期：1-2
• 页码：76-83
• 全文大小：265 K

文摘

The effect of Botulinum Toxin type A (BoNT/A) on pain and neurogenic vasodilatation induced by application to the human skin of thermal stimuli and capsaicin was evaluated in a double blind study. A capsaicin cream (0.5 ml of a 0.075 % ) was applied to the skin of both forearms of eighteen subjects randomly pretreated with either BoNT/A (Botox^®) or 0.9 % saline (NS). Capsaicin was applied to a skin area either inside (protocol A) or adjacent to the BoNT/A treated area (protocol B). Pre-treatment with BoNT/A did not affect thermal-specific and thermal-pain thresholds (by quantitative sensory testing). 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. In Protocol B, capsaicin-induced pain was unchanged, and capsaicin-induced flare/increase in CBF were reduced only in the area treated with BoNT/A, but not in the BoNT/A untreated area. Results indicate that (i) BoNT/A reduces capsaicin-induced pain and neurogenic vasodilatation without affecting the transmission of thermal and thermal-pain modalities; (ii) reduction in capsaicin-induced pain occurs only if capsaicin is administered into the BoNT/A pretreated area; (iii) reduction in neurogenic vasodilatation by BoNT/A does not contribute to its analgesic action. BoNT/A could be tested for the treatment of conditions characterised by neurogenic inflammation and inflammatory pain.