Abstract
Antinociceptive effects of peroral administration of an oriental medicine Kei-Kyoh-Zoh-Soh-Oh-Shin-Bu-toh (TJ-8023) were examined using rats and mice. TJ-8023 (100mg·kg-1·d-1) inhibited the induction of adjuvant-induced hyperalgesia of rats in the paw-pressure test following prophylactic administration, and normalized the nociceptive threshold at a dose of 600 mg·kg-1·d-1, without effects on adjuvant-induced inflammation. Mice suffering from repeated cold stress showed a decrease in nociceptive threshold for tail-pressure stimulation. Such a hyperalgesia was reversed by a single (30 and 100mg/kg) or repeated administration (100 and 300 mg·kg-1·d-1) of TJ-8023. The nociceptive threshold of non-stressed mice was not affected by TJ-8023 (100mg/kg). Nociceptive responses of mice to cold-plate stimulation were also not affected by repeated administration of TJ-8023 (300, 600 and 1200 mg·kg-1·d-1). The present results demonstrate the antinociceptive action of TJ-8023, and suggest that it is more effective in easing a hyperalgesia in morbid state than in suppressing a nociception in the normal one.
