Activational action of testosterone on androgen receptors protects males preventing temporomandibular joint pain

Autor(es)

Fanton, L. E. ; Macedo, C. G. ; Torres-Chavez, K. E. ; Fischer, L. ; Tambeli, C. H.

• Tipo de documento: Artigo Científico
• Fonte: Pharmacology Biochemistry and Behavior; v. 152, p. 6-pg., 2017-01-01.

Resumo

Background: Testosterone protects male rats from Temporomandibular Joint (TMJ) pain. This study investigated whether this protective effect is mediated by an organizational action of testosterone during nervous system development, by central estrogen and androgen receptors and by the 5 alpha-reduced metabolite of testosterone, dihydrotestosterone. Methods: A pharmacological approach was used to assess the ability of the androgen receptor antagonist flutamide, the estrogen receptor antagonist ICI 182 780 and the 5-alpha reductase inhibitor dutasteride to block the protective effect of testosterone, evaluated through the behavioral response induced by a TMJ injection of 0.5% formalin. Flutamide and ICI 182 780 were injected into the medullary subarachnoid space, and dutasteride and testosterone were systemically administered. Results: The TMJ injection of 0.5% formalin induced a significant nociceptive behavioral response in gonadectomized male and naive female, but not in sham gonadectomized male rats, confirming that endogenous testosterone prevents TMJ nociception in males. Testosterone administration prevented formalin-induced TMJ nociception in males gonadectomized either in the neonatal (at the day of birth) or adult period and in naive female rats, suggesting that the protective effect of testosterone on TMJ nociception does not depend on its organizational actions during critical periods of development. The administration of flutamide and dutasteride but not of ICI 182 780 blocked the protective effect of testosterone. Conclusions: We conclude that the protective effect of testosterone on TMJ nociception depends on activational actions of dihydrotestosterone on androgen receptors rather than on organizational androgenic actions during central nervous system development or estrogenic actions. (C) 2016 Elsevier Inc. All rights reserved. (AU)

• Processo FAPESP: 07/57517-4 - Estudo dos mecanismos envolvidos no efeito protetor da testosterona sobre o desenvolvimento da dor da atm em ratos.
• Beneficiário: Letícia Esmanhoto Fanton
• Modalidade de apoio: Bolsas no Brasil - Mestrado