Antinociceptive effect induced by intraperitoneal administration of vitamin K-2 (menatetrenone) in ICR mice

The antinociceptive effect of vitamin K-2 (menatetrenone) in mice was exami ned using tail-flick and formalin test. Menatetrenone at doses of 10, 50 an d 100 mg/kg, i.p. produced a dose-dependent and significant inhibition of t he tail-flick response in mice. Menatetrenone (50 and 100 mg/kg, i.p.) had no significant effect on the duration of the first phase of the formalin-in duced flinching. However, menatetrenone (100 mg/kg, i.p.) significantly inh ibited the second phase of the formalin-induced flinching. I.p. administrat ion of menatetrenone (100 mg/kg) significantly reduced the duration of noci ceptive responses induced by i.t. injection of bradykinin, but not of subst ance P, prostaglandin E-2 or N-methyl-D-aspartate (NMDA). These present dat a suggest that i.p. pretreatment with menatetrenone produced dose-dependent antinociceptive effect in mice. This effect may be, at least in part, medi ated by the inhibition of bradykinin dependent nociceptive transmission in the spinal cord. (C) 2000 Elsevier Science Inc. All rights reserved.