Antinociceptive and anxiolytic-like effects of Lavandula angustifolia essential oil on rat models of orofacial pain.

Background: Nociceptive and inflammatory orofacial pain is highly prevalent in the population, which justifies the search for safer analgesics. There is increasing evidence of the analgesic and anxiolytic potential of Lavandula angustifolia essential oil (LAV EO), which may represent, when administered through inhalation, may represent a safer alternative for pain treatment.

Objective: to evaluate whether LAV EO has antinociceptive effect in the formalin test, and anti-hyperalgesic and anxiolytic-like effects in rats subjected to a model of orofacial postoperative pain.

Trigeminal neuropathic pain reduces 50-kHz ultrasonic vocalizations in rats, which are restored by analgesic drugs.

Trigeminal neuralgia (TN) is a severe form of neuropathic pain frequently associated with anxiety. The chronic constriction injury of the infraorbital nerve (CCI-ION) of rodents is a well-established model to study sensory alterations related to TN. However, few studies have addressed the emotional component of pain, which is fundamental to increase its translational capability.

Blockade of kappa opioid receptors reduces mechanical hyperalgesia and anxiety-like behavior in a rat model of trigeminal neuropathic pain.

It has been shown that kappa opioid receptor (KOR) antagonists, such as nor-binaltorphimine (nor-BNI), have antinociceptive effects in some pain models that affect the trigeminal system. Also, its anxiolytic-like effect has been extensively demonstrated in the literature. The present study aimed to investigate the systemic, local, and central effect of nor-BNI on trigeminal neuropathic pain using the infraorbital nerve constriction model (CCI-ION), as well as to evaluate its effect on anxiety-like behavior associated with this model.