title: Melatonin Alters the Mechanical and Thermal Hyperalgesia Induced by Orofacial Pain Model in Rats.
abstract: Melatonin is a neuroendocrine hormone that presents a wide range of physiological functions including regulating circadian rhythms and sleep, enhancing immune function, sleep improvement, and antioxidant effects. In addition, melatonin has received special attention in pain treatment since it is effective and presents few adverse effects. In this study, we evaluated the effect of acute dose of melatonin upon hyperalgesia induced by complete Freund's adjuvant in a chronic orofacial pain model in Sprague-Dawley rats. Nociceptive behavior was assessed by facial Von Frey and the hot plate tests at baseline and thereafter 30, 60, and 120 min, 24 h, and 7 days after melatonin treatment. We demonstrated that acute melatonin administration alters mechanical and thermal hyperalgesia induced by an orofacial pain model (TMD), highlighting that the melatonin effect upon mechanical hyperalgesia remained until 7 days after its administration. Besides, we observed specific tissue profiles of neuroimmunomodulators linked to pain conditions and/or melatonin effect (brain-derived neurotrophic factor, nerve growth factor, and interleukins 6 and 10) in the brainstem levels, and its effects were state-dependent of the baseline of these animals.
authors.affiliation: Postgraduate Program in Biological Sciences: Physiology, Health Basic Sciences Institute, Universidade Federal do Rio Grande do Sul, Porto Alegre, 90050-170, Brazil.|Laboratory of Pain Pharmacology and Neuromodulation: Preclinical Research, Pharmacology Department, Health Basic Sciences Institute, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500 sala 305, Porto Alegre, 90050-170, RS, Brazil.|Animal Experimentation Unit and Graduate Research Group, Hospital de Clínicas de Porto Alegre, Porto Alegre, 90035-003, RS, Brazil.
authors.forename: Vanessa Leal
authors.initials: VL
authors.lastname: Scarabelot
authors.affiliation: Laboratory of Pain Pharmacology and Neuromodulation: Preclinical Research, Pharmacology Department, Health Basic Sciences Institute, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500 sala 305, Porto Alegre, 90050-170, RS, Brazil.|Animal Experimentation Unit and Graduate Research Group, Hospital de Clínicas de Porto Alegre, Porto Alegre, 90035-003, RS, Brazil.
authors.forename: Liciane Fernandes
authors.initials: LF
authors.lastname: Medeiros
authors.affiliation: Laboratory of Pain Pharmacology and Neuromodulation: Preclinical Research, Pharmacology Department, Health Basic Sciences Institute, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500 sala 305, Porto Alegre, 90050-170, RS, Brazil.|Animal Experimentation Unit and Graduate Research Group, Hospital de Clínicas de Porto Alegre, Porto Alegre, 90035-003, RS, Brazil.|Postgraduate Program in Medical Sciences, School of Medicine, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Carla
authors.initials: C
authors.lastname: de Oliveira
authors.affiliation: Laboratory of Pain Pharmacology and Neuromodulation: Preclinical Research, Pharmacology Department, Health Basic Sciences Institute, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500 sala 305, Porto Alegre, 90050-170, RS, Brazil.|Animal Experimentation Unit and Graduate Research Group, Hospital de Clínicas de Porto Alegre, Porto Alegre, 90035-003, RS, Brazil.|Postgraduate Program in Medical Sciences, School of Medicine, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Lauren Naomi Spezia
authors.initials: LN
authors.lastname: Adachi
authors.affiliation: Laboratory of Pain Pharmacology and Neuromodulation: Preclinical Research, Pharmacology Department, Health Basic Sciences Institute, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500 sala 305, Porto Alegre, 90050-170, RS, Brazil.|Animal Experimentation Unit and Graduate Research Group, Hospital de Clínicas de Porto Alegre, Porto Alegre, 90035-003, RS, Brazil.
authors.forename: Isabel Cristina
authors.initials: IC
authors.lastname: de Macedo
authors.affiliation: Laboratory of Pain Pharmacology and Neuromodulation: Preclinical Research, Pharmacology Department, Health Basic Sciences Institute, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500 sala 305, Porto Alegre, 90050-170, RS, Brazil.|Animal Experimentation Unit and Graduate Research Group, Hospital de Clínicas de Porto Alegre, Porto Alegre, 90035-003, RS, Brazil.
authors.forename: Stefania Giotti
authors.initials: SG
authors.lastname: Cioato
authors.affiliation: Laboratory of Pain Pharmacology and Neuromodulation: Preclinical Research, Pharmacology Department, Health Basic Sciences Institute, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500 sala 305, Porto Alegre, 90050-170, RS, Brazil.|Animal Experimentation Unit and Graduate Research Group, Hospital de Clínicas de Porto Alegre, Porto Alegre, 90035-003, RS, Brazil.
authors.forename: Joice S
authors.initials: JS
authors.lastname: de Freitas
authors.affiliation: Laboratory of Pain Pharmacology and Neuromodulation: Preclinical Research, Pharmacology Department, Health Basic Sciences Institute, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500 sala 305, Porto Alegre, 90050-170, RS, Brazil.
authors.forename: Andressa
authors.initials: A
authors.lastname: de Souza
authors.affiliation: Laboratory of Pain Pharmacology and Neuromodulation: Preclinical Research, Pharmacology Department, Health Basic Sciences Institute, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500 sala 305, Porto Alegre, 90050-170, RS, Brazil.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Quevedo
authors.affiliation: Department of Surgery in Medical School, Universidade Federal do Rio Grande do Sul, Porto Alegre, 90035-003, RS, Brazil.
authors.forename: Wolnei
authors.initials: W
authors.lastname: Caumo
authors.affiliation: Postgraduate Program in Biological Sciences: Physiology, Health Basic Sciences Institute, Universidade Federal do Rio Grande do Sul, Porto Alegre, 90050-170, Brazil. iltorres@hcpa.edu.br.|Laboratory of Pain Pharmacology and Neuromodulation: Preclinical Research, Pharmacology Department, Health Basic Sciences Institute, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500 sala 305, Porto Alegre, 90050-170, RS, Brazil. iltorres@hcpa.edu.br.|Animal Experimentation Unit and Graduate Research Group, Hospital de Clínicas de Porto Alegre, Porto Alegre, 90035-003, RS, Brazil. iltorres@hcpa.edu.br.|Postgraduate Program in Medical Sciences, School of Medicine, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. iltorres@hcpa.edu.br.
authors.forename: Iraci Lucena da Silva
authors.initials: IL
authors.lastname: Torres
mesh_terms: D000818:Animals; D001933:Brain Stem / Q000378:metabolism; D005157:Facial Pain / Q000150:complications*; D005620:Freund's Adjuvant; D006930:Hyperalgesia / Q000139:chemically induced / Q000188:drug therapy*; D008550:Melatonin / Q000494:pharmacology* / Q000627:therapeutic use; D015213:Neuroimmunomodulation / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D005620:Freund's Adjuvant; D008550:Melatonin
keywords: chronic pain; melatonin; neuroimmunomodulators; orofacial pain; temporomandibular disorder; temporomandibular joint