title: Gabapentin decreases microglial cells and reverses bilateral hyperalgesia and allodynia in rats with chronic myositis.
abstract: In the present work, we investigated the antinociceptive effect of gabapentin in a chronic myositis model and its interference in spinal glial cells. Chronic myositis was induced by injection of Complete Freund Adjuvant (CFA) into the right gastrocnemius (GS) muscle of rats and tests for evaluating mechanical hyperalgesia, thermal hyperalgesia and tactile allodynia were performed. Pharmacological treatment with gabapentin was administrated intrathecally and 100μg and 200μg doses were tested. For analyzing astrocytes and microglia in the spinal cord, immunochemistry assay was performed. It was found that gabapentin 200μg reverted CFA-induced chronic muscle pain bilaterally, in all applied tests and it was able to attenuate microglial but not astrocytes activation in the dorsal horn of spinal cord. In conclusion, gabapentin was able to inhibit hyperalgesia and allodynia in chronic myositis and also to attenuate spinal microglial activation. Therefore, gabapentin could be used as treatment for targeting chronic muscle pain.
authors.affiliation: Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil.
authors.forename: A S
authors.initials: AS
authors.lastname: Rosa
authors.affiliation: Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil.
authors.forename: M F
authors.initials: MF
authors.lastname: Freitas
authors.affiliation: Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil.
authors.forename: I R C
authors.initials: IR
authors.lastname: Rocha
authors.affiliation: Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil. Electronic address: chacurm@icb.usp.br.
authors.forename: M
authors.initials: M
authors.lastname: Chacur
mesh_terms: D000588:Amines / Q000494:pharmacology* / Q000627:therapeutic use; D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000473:pathology; D001522:Behavior, Animal / Q000187:drug effects; D002452:Cell Count; D002908:Chronic Disease; D003509:Cyclohexanecarboxylic Acids / Q000494:pharmacology* / Q000627:therapeutic use; D000077206:Gabapentin; D006930:Hyperalgesia / Q000150:complications / Q000188:drug therapy* / Q000473:pathology*; D008297:Male; D017628:Microglia / Q000187:drug effects* / Q000473:pathology*; D063806:Myalgia / Q000150:complications; D009220:Myositis / Q000150:complications*; D051381:Rats; D017208:Rats, Wistar; D066148:Spinal Cord Dorsal Horn / Q000473:pathology; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology* / Q000627:therapeutic use
chemical_list: D000588:Amines; D003509:Cyclohexanecarboxylic Acids; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin
keywords: Allodynia; Astrocytes; Chronic muscle pain; Gabapentin; Hyperalgesia; Microglia