• Biomolecules & Therapeutics
• /
• 제5권1호
• /
• pp.12-22
• /
• 1997

Intravenous and oral acute toxicity tests in ICR mice and SD rats and percutaneous acute toxicity tests in SD rats and NZW rabbits were conducted to evaluate the toxicity of DA-5018 and DA-5018 cream, respectively Clinical signs observed in mice and rats after the administration of DA-5018 were similar regardless of administration route. The observed clinical signs were jumping, wild running, lacrimation, ataxia, reddening of extremities and ears, ventral or lateral recumbency, respiratory distress, cyanosis, convulsion and death. Pulmonary enlargement and hemorrhage were observed in the animals died immediately after the dosing of DA-5018. At terminal necropsy, pulmonary enlargement and hemorrhage, corneal opacity and focal scabbing and depilation around nose were seen. LD$_{50}$ Values of DA-5018 are 11.5 mg/kg (mice, male), 12.6 mg/kg (mice, female), 88.3 mg/kg (rat, male) and 73.2 mg/kg (rat, female) in oral toxicity tests and 11.0 mg/kg (mice, male), 18.7 mg/kg (mice, female), 0.12 mg/kg (rat, male) and 0.32 mg/kg (rat, female) in i.v. toxicity tests. In the percutaneous acute toxicity tests of DA-5018 cream, no deaths occured in all the tested groups during 14-day observation period. There were also no abnormalities in the general conditions, body weight changes and on necropsy findings in all groups. LD$_{50}$ values of 0.1 ~0.9% DA-5018 creams in male and female rats and rabbits are >2000 mg/kg./kg.

• Biomolecules & Therapeutics
• /
• 제5권1호
• /
• pp.94-99
• /
• 1997

Capsaicin is known to be an analgesic agent, affecting the synthesis, storage, , transport and release of substance p, the principal neurotransmitter of pain from periphery to the central nervous system(CNS). DA-5018, a newly synthesized capsaicin derivative has shown potent analgesic effect comparable to that of morphine in various rat models of experimentally inducted acute pairs. In this study the mechanism of analgesic actlvity of DA-5018 was examined. First, the electrically-evoked contraction of guinea pig trachea was inhibited by DA-5018 and these inhibition was recovered by incubation with capsafepine(3$\muM$), capsaicin receptor antagonist and this result suggested that DA-5018 has affinity on capsaicin receptor. The correlation between the norciceptive threshold and the release of substance P was evaluated. In vivo perfusion of slices of the rat spinal cord with DA-5018(10, 100$\muM$) produced a significant increase of the release of substance P and this increase was less than that of capsaicin(10$\muM$). The norciceptive threshold of rat treated with DA-5018(1 mg/kg, p.o) in tall pinch test increased from 2.9$\pm$0.3 to 23.5 $\pm$6.61. Tail pinch latency increased to a maximun at 15 min after DA-5018 treatment and then declined to control values by 120 min. The capsaicin-evoked release ot substance P from the spinal cord slices of rat treated with DA-5018 reduced from 2.38$\pm$ 0.79 to 0.69$\pm$ 0.26 pg/mg wet weight. This reduction reached to a minium at 15 min after DA-5018 treatment and then recovered to control value by 120 min. These results mean that analgesic activity of DA-5018 is due to release of substance P The effect of DA-5018 cream on electrically-evoked neurogenic inflammation of rat saphenous nerve was compared with capsaicin (zostrix-HP). DA-5018 showed 34% inhibition of the neurogenic extravasation while capsaicin showed significant 67% inhibition. This result indicates that the potency of DA-5018 in the release of substance P is less than that of capsaicin. These results suggest that the release of substance P is partially involved in the mechanism of analgesic action of DA-50l8.