[Analgesic effects of Tsumura-shuuji-bushi-matsu and mesaconitine]

"Tsumura-shuuji-bushi-matsu" (TJ-3021) is a herbal medicine produced from Aconiti tuber through autoclaving to decrease its toxicity. In this study, the analgesic effects of TJ-3021 and mesaconitine (MA) was examined in rats and mice. TJ-3021 (300 mg/kg, p.o.) or MA (0.5 mg/kg, p.o.) depressed the acetic acid-induced writhing significantly. In Randall-Selitto's method, TJ-3021 (1000 mg/kg) increased the pain threshold ratio in the inflamed foot significantly but not in the normal foot. In the hot plate method or on adjuvant-induced arthritic pain, TJ-3021 (1000 mg/kg) significantly increased the pain threshold, and its effect was less than that of "nama-bushi-matsu" (TNB), which was produced from the same Aconiti tuber without autoclaving. Repeated cold stress (RCS) for 65.5 hr decreased the pain threshold ratio on the paw pressure in rats by 60%. TJ-3021 (300 mg/kg) significantly increased the pain threshold ratio in RCS rats, and its activity was almost the same degree as that of TNB. MA (0.5 mg/kg) significantly increased the pain threshold ratio in RCS rats or on the adjuvant-induced arthritic pain; and in RCS rats, it was more potent than morphine (1 mg/kg, p.o.).