(-)-α-Bisabolol reduces nociception and trigeminal central sensitisation in acute orofacial neuropathic pain induced by infraorbital nerve injury

  • Life Sci. 2019 Jun 15;227:122-128. doi: 10.1016/j.lfs.2019.04.032.
L T Melo  1 ,  V Panchalingam  2 ,  P Cherkas  2 ,  A R Campos  3 ,  L Avivi-Arber  2 ,  B J Sessle  4
Affiliations
  • 1. Experimental Biology Centre (NUBEX), University of Fortaleza (UNIFOR), Brazil; Faculty of Dentistry, University of Toronto, Canada. Electronic address: [email protected].
  • 2. Faculty of Dentistry, University of Toronto, Canada.
  • 3. Experimental Biology Centre (NUBEX), University of Fortaleza (UNIFOR), Brazil.
  • 4. Faculty of Dentistry, University of Toronto, Canada; Deparment of Physiology, University of Toronto, Canada.
PMID: 31002923 DOI: 10.1016/j.lfs.2019.04.032
Abstract

Neuropathic orofacial pain conditions represent a challenge to diagnose and treat. Natural substances are promising therapeutic options for the control of pain.

Aims: This study aimed to examine whether (-)-α-bisabolol (BISA), a natural terpene, can attenuate nociceptive behaviour and central sensitisation in a rodent model of trigeminal neuropathic pain.

Materials and methods: Infraorbital nerve transection (IONX) or sham operation was performed in adult male rats. Head withdrawal thresholds as a measure of facial mechanical sensitivity were tested with von Frey monofilaments applied bilaterally to the facial vibrissal pad pre-operatively (baseline) and then post-operatively before and at 60, 120, 240 and 360 min after administration of vehicle control per oris (p.o.) or BISA (200 mg/kg p.o.) (n = 8/group). Effects of BISA or vehicle on the activity of nociceptive neurons recorded in the medullary dorsal horn (MDH) were tested on post - operative day 8-10. ANOVA followed by post-hoc Bonferroni tested for statistically significant differences (p < 0.05) across study groups and time points.

Key findings: IONX Animals (but not sham or naïve Animals) showed post-operative facial mechanical hypersensitivity that was unaffected by vehicle. However, administration of BISA at post-operative day 7 significantly reversed the mechanical hypersensitivity in IONX rats; this effect lasted for at least 6 h. BISA also attenuated IONX-induced central sensitisation of MDH nociceptive neurons, as reflected in reversal of their reduced activation thresholds, increased responses to graded mechanical stimuli and enhanced spontaneous activity.

Significance: BISA may attenuate nociceptive behaviour and central sensitisation in a rat model of acute trigeminal neuropathic pain.

Keywords
(−)-α-Bisabolol; Behaviour; Central sensitisation; Trigeminal neuropathic pain.
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