In an attempt to provide more direct evidence concerning the possible antinociceptive effect of
resveratrol-
benfotiamine combination on neurogenic
pain, we investigated whether
resveratrol and
benfotiamine administered alone or in combination decrease
capsaicin induced nociception in mice. Before testing, the animals were placed individually in transparent glass cylinders, 20 cm in diameter, serving as observation chambers. After the adaptation period, 20 microL of
capsaicin (1.6 microg/paw) were injected under the skin of the dorsal of the right hind paw. Animals were observed individually for 5 min after
capsaicin injection. The amount of time spent licking the injected paw was timed with a chronometer and was considered as indicative of nociception. Animals were pretreated with
resveratrol (56.2-177 mg/kg, i.p.),
benfotiamine (100-1000 mg/kg, p.o.) and their combinations (11:1, 22:2, 44:4; 88:8 mg/kg
benfotiamine:
resveratrol). It was observed that
resveratrol (ED50 = 104 +/- 8.2 mg/kg) was able to produce more important decrement of
capsaicin-induced licking than
benfotiamine (ED50 = 529.4 +/- 85.2 mg/kg). In addition, a synergistic interaction was observed between
benfotiamine and
resveratrol, suggesting that this combination could be useful in neurogenic nociception.