Analgesic effect of processed Aconiti tuber in rats with neuropathic pain / 中华麻醉学杂志

ABSTRACT

Objective To investigated the analgesic effect of processed Aconiti tuber(PAT) in rats with a sciatic nerve chronic constriction injury(CCI) .Methods The study was conducted in two parts. CCI model was developed with four ligatures placed around the right sciatic nerve and tied without obstructing the blood supply of the nerve. In part Ⅰ, forty rats were randomly divided into five groups(n = 8) . In group Ⅰ normal saline 1 ml , In group Ⅱ-Ⅴ PAT 0.5 ,1, 2 ,or 4 g/kg was administered orally 14 days after CCI respectively. In part Ⅱ , thirty-two rats were randomly divided into four groups (n = 8) . In group Ⅰ oral normal saline 1 ml, in group Ⅱ oral PAT 2 g/kg, in group Ⅲ oral PAT 2 g/kg + intraperitoneal nor-binaltorphimine (nor-BNI) 2 mg/kg, in group Ⅳ oral PAT 2 g/kg + intrathecal nor-BNI 100 ?g was administered 14 days after CCI. As indicators of mechanical and heat hyperalgesia, the paw withdrawal pressure threshold (PWPT) in response to a graded pressure stimulus with a filament and the paw withdrawal latency (PWL) in response to radiant heat were measured in both hind paws before and after drugs administration.Results In part Ⅰ, in group Ⅲ-Ⅴ PWL was prolonged significantly and in group Ⅳ - Ⅴ PWPT were significantly increased compared with those in group I . There was no significant difference in PWL and PWPT between group Ⅰ and group Ⅱ . In part Ⅱ , in group Ⅲ, Ⅳ PWPT and PWL were significantly lower than those in group Ⅱ . There was no significantly difference in PWL and PWPT between group Ⅰ and group Ⅲ, Ⅳ . Conclusion In rat with neuropathic pain processed Aconiti tuber exerts analgesic effect via the spinal ?-opioid receptor activation.