Anti-nociceptive effect of patchouli alcohol: Involving attenuation of cyclooxygenase 2 and modulation of mu-opioid receptor

Objective To explore the anti-nociceptive effect of patchouli alcohol (PA), the essential oil isolated from Pogostemon cablin (Blanco) Bent, and determine the mechanism in molecular levels. Methods The acetic acid-induced writhing test and formalin-induced plantar injection test in mice were employed to confirm the effect in vivo . Intracellular calcium ion was imaged to verify PA on mu-opioid receptor (MOR). Cyclooxygenase 2 (COX2) and MOR of mouse brain were expressed for determination of PA’s target. Cellular experiments were carried out to find out COX2 and MOR expression induced by PA. Results PA significantly reduced latency period of visceral pain and writhing induced by acetic acid saline solution ( P