Effect of myrcene on nociception in mice.

Myrcene, a monoterpene isolated from lemon grass oil (Cymbopogon citratus) has been investigated for antinociception in mice by a low temperature (51.5 +/- 0.5 degrees C) hot plate method and by the acetic acid-induced writhing test. Significant inhibition of nociception was seen in the tests with myrcene at doses of 10 and 20 mg kg-1 (i.p.) or at 20 and 40 mg kg-1 (s.c.), respectively. The antinociceptive effect was significantly antagonized by naloxone (1 mg kg-1) or yohimbine (2 mg kg-1). The results suggest that myrcene is capable of inducing antinociception in mice, probably mediated by alpha 2-adrenoceptor stimulated release of endogenous opioids.