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Tang W, Song B, Zhou ZS, Lu GS. Chin Med J (Engl). 2007 Sep
20;120(18):1616-21.
Intrathecal administration of resiniferatoxin produces
analgesia against prostatodynia in rats.
Urological Research Institute of PLA, Southwest Hospital,
Third Military Medical University, Chongqing, China.
BACKGROUND: Prostatodynia remains a difficult clinical
problem. Resiniferatoxin (RTX), an ultrapotent vanilloid, can
produce a selective and long-lasting desensitization of
nociception via C-fiber sensory neurons. Substance P (SP) and
calcitonin gene-related peptide (CGRP) released from C-fibers
are key neurotransmitters in visceral pain. In this study, we
evaluated the analgesic effect of intrathecal RTX on rat
prostatodynia.
METHODS: Male Sprague-Dawley rats were divided into 3 groups
for different treatment. In group A, sham operation was
preformed. In group B, 100 microl complete Freund's adjuvant
(CFA) was injected into the rat's bilateral ventral prostate to
induce chronic inflammation. In group C, after prostatitis
formed, 50 microl 10 nmol/L RTX was injected into the rat's
lumbosacral (L5-S2) vertebral canal. SP and CGRP contents in the
spinal cord were investigated by immunohistochemistry and
radioimmunoassay (RIA). Their transcriptional levels in dorsal
root ganglion (DRG) were determined by reverse transcriptase
polymerase chain reaction (RT-PCR). In addition, pelvic nerve
afferent discharge was recorded to explore the neuro-electrophysiological
mechanisms underlying RTX-induced effect.
RESULTS: SP and CGRP released in the spinal cord and their
synthesis in DRG were increased significantly in response to
CFA-induced chronic prostatitis, whereas this increase was
effectively inhibited by intrathecal RTX. Meanwhile, pelvic
nerve afferent electrical activity was enhanced significantly in
rats with chronic prostatitis, but it was attenuated markedly in
RTX-treated rats paralleled by the change of neuropeptides.
CONCLUSIONS: Intrathecal RTX administration could produce an
analgesic effect on rat prostatodynia. Suppression of pelvic
nerve afferent electrical activity may be a crucial mechanism
underlying RTX-induced analgesia. RTX intrathecal application
may present a novel analgesic strategy of prostatodynia.
PMID: 17908482 |
