Antinociceptive effect of p‐cymene in mice – evidence of involvement of periaqueductal gray area

Abstract

p‐Cymene (PC) is a monoterpene present in the essential oil of many aromatic medicinal plants. We investigated the anti‐hypernociceptive effect of PC and your action in the central nervous system (CNS) in rodents. Male mice were pretreated with PC (25, 50 and 100 mg/kg, i.p.), morphine (5 mg/kg, i.p.) or vehicle (distilled water + one drop of Tween 80 0.2%), 1h before of mechanic hypernociception induction by carrageenan (CG), TNF‐α, prostaglandin (PGE2) and dopamine (DA). Experimental protocols were approved by the Animal Care and Use Committee at the Federal University of Sergipe (CEPA#19/11). The data were analyzed by ANOVA (two‐way) followed by Tukey's test (p<0.05). Our results revealed that acute treatment with PC, all doses, reduced significantly the hypernociception (p<0.01 or p<0.001) caused by CG, TNF‐α, PGE2 and DA. Such results were unlikely to be provoked by motor abnormality. The immunofluorescence assay demonstrated a significant increase in the number of Fos positive cells (p<0.05 or p<0.01) in the periaqueductal gray. Together, our results provide evidence to show that PC attenuates nociception at least through an activation of CNS area, mainly periaqueductal gray.