فهرست نشریات علمی دسترسی آزاد ایران

Previous findings have shown that saffron ( Crocus sativus L.) extract and its active constituents produce antinociceptive effects in the rat models of orofacial pain. In the present study, the central H 2 histaminergic and alpha-2 adrenergic receptors involvement in crocetin-induced antinociception in orofacial formalin pain in rats was evaluated.The guide cannula was implanted into the fourth ventricle in ketamine-xylazine anesthetized rats. Subcutaneous injection of a diluted formalin solution (1.50%; 50.00 µL) into a vibrissa pad was used as a model of orofacial pain. Face rubbing behavior durations were recorded at 3 min blocks for 45 min.Formalin produced a biphasic pain response (first phase: 0-3 min and second phase: 15-33 min). Intra-fourth ventricle injections of crocetin (5.00 and 10.00 μg μL -1 ) suppressed, whereas yohimbine (10.00 μg μL -1 ) and naloxone (10.00 μg μL -1 ) increased the intensity of both phases of pain. Crocetin-induced antinociception was not prevented by central pretreatment with naloxone. However, the antinociceptive effect of crocetin (5.00 μg μL -1 ) was inhibited by prior administration of famotidine (10.00 μg μL -1 ) and yohimbine (10.00 μg μL -1 ). Our study showed that injection of crocetin into the cerebral fourth ventricle attenuated formalin-induced orofacial pain in rats. Central H 2 histaminergic and alpha-2 adrenergic receptors, but not opioid receptors, might be involved in crocetin-induced antinociception.