Orexin-A inhibits capsaicin-induced changes in cyclooxygenase-2 and brain-derived neurotrophic factor expression in trigeminal nucleus caudalis of rats
10.3344/kjp.2018.31.3.174
- Author:
Razieh KOOSHKI
1
;
Mehdi ABBASNEJAD
;
Saeed ESMAEILI MAHANI
;
Maryam RAOOF
;
Mohammad Mehdi MOEINI AGHTAEI
;
Shahriar DABIRI
Author Information
1. Department of Biology, Faculty of Sciences, Shahid Bahonar University of Kerman, Kerman, Iran.
- Publication Type:Original Article
- Keywords:
Brain-derived neurotrophic factor (BDRF);
Capsaicin;
Cyclooxygenase 2 (COX 2);
Orexin-A;
Orexin receptor antagonists;
Orofacial pain;
Rats;
Pain measurement;
Pain perception;
Trigeminal caudal nucleus;
Trigeminal neuralgia
- MeSH:
Animals;
Brain-Derived Neurotrophic Factor;
Capsaicin;
Cyclooxygenase 2;
Facial Pain;
Fluorescent Antibody Technique;
Injections, Subcutaneous;
Lip;
Microinjections;
Nociceptors;
Orexin Receptor Antagonists;
Orexins;
Pain Measurement;
Pain Perception;
Rats;
Trigeminal Caudal Nucleus;
Trigeminal Neuralgia;
Trigeminal Nuclei
- From:The Korean Journal of Pain
2018;31(3):174-182
- CountryRepublic of Korea
- Language:English
-
Abstract:
BACKGROUND: The trigeminal nucleus caudalis (Vc) is a primary central site for trigeminal transmitting. Noxious stimulation of the trigeminal nociceptors alters the central synaptic releases and neural expression of some inflammatory and trophic agents. Orexin-A and the orexin 1 receptor (OX1R) are expressed in pain pathways including trigeminal pain transmission. However, the the mechanism(s) underling orexin-A effects on trigeminal pain modulation have not been fully clarified. METHODS: Trigeminal pain was induced by subcutaneous injection of capsaicin in the upper lip in rats. The effect of trigeminal pain on cyclooxygenase-2 (COX-2) and brain-derived neurotrophic factor (BDNF) expression in the Vc of animals was determined by immunofluorescence. Subsequently, OX1R agonist (orexin-A) and antagonist (SB-334867-A) was administrated in the Vc to investigate the possible roles of the Vc OX1R on changes in COX-2 and BDNF levels following pain induction. RESULTS: The data indicated an increase in COX-2 and decrease in BDNF immuno-reactivity in the Vc of capsaicin, and capsaicin- pretreated with SB-334867-A (80 nM), groups of rat. However, the effect of capsaicin on COX-2 and BDNF expressions was reversed by a Vc microinjection of orexin-A (100 pM). CONCLUSIONS: Overall, the present data reveals that orexin-A can attenuate capsaicin-induced trigeminal pain through the modulation of pain effects on COX-2 and BDNF expressions in the Vc of rats.
