Central antalgic activity of resveratrol.

A single dose of resveratrol (25 μg/10μl) was injected directly into the right lateral cerebral ventricle (icv) of Wistar rats via an implanted cannula in order to study the analgesic properties of the compound. A control group of rats received 10 μl NaCl 0.9%. The lengthening of the time to reaction to painful stimuli was assessed in the radiant heat tail-flick latency time test. In this study, the response to painful stimuli of the animals treated with resveratrol had a bimodal profile with hypoalgesia or hyperalgesia. In the selected experimental conditions, resveratrol had a definite analgesic effect; the increase in time to reaction ranged from 100-120% (8 rats) to 600-700% (9 rats). In this experiment resveratrol exerts evident central antalgic effects in the majority of rats, which are related to the individual level of excitation and vigilance at baseline. Antinociceptive induced by resveratrol icv injection was maximal at 4-10 min and lasted no longer than 15 min. The effect of resveratrol to produce analgesia after a single icv injection may be interesting for preventing chronic pain.