Perineural resiniferatoxin prevents hyperalgesia in a rat model of postoperative pain

I Kissin, N Davison, EL Bradley Jr - Anesthesia & Analgesia, 2005 - journals.lww.com
I Kissin, N Davison, EL Bradley Jr
Anesthesia & Analgesia, 2005journals.lww.com
IMPLICATIONS: We found that resiniferatoxin prevents pain caused by incision. Vanilloid
agonists provide a type of neural blockade when postoperative pain is abolished while
preserving nonpainful sensations and motor functions. Resiniferatoxin (RTX) is a vanilloid
agonist with a unique spectrum of activities (1, 2). Vanilloid agonists can produce selective
and long-lasting neural blockade (1). Several studies have demonstrated that perineural
administration of another vanilloid, capsaicin, can selectively block the conduction of …
IMPLICATIONS: We found that resiniferatoxin prevents pain caused by incision. Vanilloid agonists provide a type of neural blockade when postoperative pain is abolished while preserving nonpainful sensations and motor functions.
Resiniferatoxin (RTX) is a vanilloid agonist with a unique spectrum of activities (1, 2). Vanilloid agonists can produce selective and long-lasting neural blockade (1). Several studies have demonstrated that perineural administration of another vanilloid, capsaicin, can selectively block the conduction of impulses in the C fibers and A-δ fibers at the site of capsaicin application (3–5). The question central to the prospective use of vanilloid agonists for neural blockade in postoperative pain is their ability to inhibit mechanical hyperalgesia during incisional inflammation. Reports on the effect of capsaicin-induced nerve blockade are usually limited to studies of the blockade of the responses to noxious heat stimuli. Previous studies have reported contradictory results regarding the effect of capsaicin (applied to a peripheral nerve) on responses to noxious mechanical stimuli; Fitzgerald and Woolf (6) reported that noxious mechanical stimuli were unaffected by capsaicin, whereas Chung et al.(4) observed an inhibitory effect. In our previous study (7), the percutaneous administration of RTX (0.001%) to a peripheral nerve in rats provided long-lasting suppression of not only thermal, but also mechanical nociception (although to a lesser degree). We also found that a perineural injection of RTX completely prevented carrageenan-induced hyperalgesia (including mechanical hyperalgesia) without producing any abnormality in walking.
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