Aim To study the effects of tetrodotoxin （TTX） combined with acetylsalicylic acid （ASA） on nociceptive stimulus in mice. Methods To assess the antinociceptive effects of TTX, ASA or TTX plus ASA, the acetic acid-i...Aim To study the effects of tetrodotoxin （TTX） combined with acetylsalicylic acid （ASA） on nociceptive stimulus in mice. Methods To assess the antinociceptive effects of TTX, ASA or TTX plus ASA, the acetic acid-induced abdominal constriction test and formalin pain test were used. Results TTX （0.5 - 4.0 μg· kg^-1 ） or ASA （25 - 200 mg· kg^-1 ） im produced a significant inhibition of acetic acid-induced abdominal constriction. The median inhibitory doses （ID508） were 2.1 μg· kg^-1 for TTX（ and 64 mg· kg^-1 for ASA. TTX and ASA also showed a dose-dependent inhibition of the second phase response in the formalin pain model, the ID508, being 2.3μg·kg^-1 and 74.2 mg· kg^-1, respectively. The ihteraction between TTX and ASA was synergistic, as evidenced by the fact that （1） when ASA alone compared with the combination of TTX （0.79 μg · kg^-1 or 0.39μg· kg^-1 ） and ASA, the ID508, of ASA reduced from 64.0 mg· kg^-1 to 5.8 mg· kg^-1 or 12.6 mg· kg^-1, and from 74.2 mg· kg^-1 to 7.4 mg· kg^-1 or 13.0 mg· kg^-1 on tile two models of nociceptive tests, respectively; and that （2） synergism in the analgesic effects was shown by isobiolographic analysis. Conclusion TTX, ASA and the combination of the two drags produce analgesic effects in acetic acid-induced abdominal constriction test and formalin-induced pain test. The interactions between TTX and ASA may be useful in developing novel analgesic agents.展开更多
文摘Aim To study the effects of tetrodotoxin （TTX） combined with acetylsalicylic acid （ASA） on nociceptive stimulus in mice. Methods To assess the antinociceptive effects of TTX, ASA or TTX plus ASA, the acetic acid-induced abdominal constriction test and formalin pain test were used. Results TTX （0.5 - 4.0 μg· kg^-1 ） or ASA （25 - 200 mg· kg^-1 ） im produced a significant inhibition of acetic acid-induced abdominal constriction. The median inhibitory doses （ID508） were 2.1 μg· kg^-1 for TTX（ and 64 mg· kg^-1 for ASA. TTX and ASA also showed a dose-dependent inhibition of the second phase response in the formalin pain model, the ID508, being 2.3μg·kg^-1 and 74.2 mg· kg^-1, respectively. The ihteraction between TTX and ASA was synergistic, as evidenced by the fact that （1） when ASA alone compared with the combination of TTX （0.79 μg · kg^-1 or 0.39μg· kg^-1 ） and ASA, the ID508, of ASA reduced from 64.0 mg· kg^-1 to 5.8 mg· kg^-1 or 12.6 mg· kg^-1, and from 74.2 mg· kg^-1 to 7.4 mg· kg^-1 or 13.0 mg· kg^-1 on tile two models of nociceptive tests, respectively; and that （2） synergism in the analgesic effects was shown by isobiolographic analysis. Conclusion TTX, ASA and the combination of the two drags produce analgesic effects in acetic acid-induced abdominal constriction test and formalin-induced pain test. The interactions between TTX and ASA may be useful in developing novel analgesic agents.
