This study aims to identify the inhibitory role of the spinal glucagon like peptide-1 receptor (GLP-1R) signaling in pain hypersensitivity and its mechanism of action in rats and mice. First, GLP-1Rs were identified to be specifically expressed on microglial cells in the spinal dorsal horn, and profoundly upregulated after peripheral nerve injury. In addition, intrathecal GLP-1R agonists GLP-1(7-36) and exenatide potently alleviated formalin-, peripheral nerve injury-, bone cancer-, and diabetes-induced hypersensitivity states by 60 -90%, without affecting acute nociceptive responses. The antihypersensitive effects of exenatide and GLP-1 were completely prevented by GLP-1R antagonism and GLP-1R gene knockdown. Furthermore, exenatide evoked ␤-endorphin release from both the spinal cord and cultured microglia. Exenatide antiallodynia was completely prevented by the microglial inhibitor minocycline, ␤-endorphin antiserum, and opioid receptor antagonist naloxone. Our results illustrate a novel spinal dorsal horn microglial GLP-1R/␤-endorphin inhibitory pathway in a variety of pain hypersensitivity states.

Objective: To investigate the effects of exenatide on blood glucose, body weight and hepatic enzymes in patients with type 2 diabetes mellitus (T2DM) and concomitant non-alcoholic fatty liver disease (NAFLD). Subjects and methods: One hundred and seventeen patients with T2DM and NAFLD were randomly divided into exenatide group and metformin group. Patients were treated with exenatide and metformin, respectively, for 12 weeks. Results: After 12 weeks of treatment, body weight, body mass index (BMI), waist-to-hip ratio, HbA1c, FPG, 2-h PPG, ALT, AST, γ-GT, and hs-CRP were significantly reduced, and the AST/ALT ratio and adiponectin were markedly increased in both groups. BMI, waist-to-hip ratio, 2-h PPG, ALT, AST, γ-GT, and hs-CRP were markedly lower, and AST/ ALT ratio and adiponectin in the exenatide group were dramatically higher than in the metformin group. Conclusion: Compared with metformin, exenatide is better to control blood glucose, reduces body weight and improves hepatic enzymes, attenuating NAFLD in patients with T2DM concomitant with NAFLD. Arq Bras Endocrinol Metab. 2013;57(9):702-8 Keywords Exenatide; metformin; non-alcoholic fatty liver disease; type 2 diabetes mellitus RESUMO Objetivo: Investigar os efeitos do exenatide sobre a glicose sérica, peso corporal e enzimas hepá-ticas em pacientes com diabetes melito tipo 2 (T2DM) e doença hepática gordurosa não alcoólica (DHGNA). Sujeitos e métodos: Um total de 117 pacientes com T2DM e DHGNA foi aleatoriamente separado em dois grupos, um tratado com exenatide e um tratado com metformina. Os pacientes foram tratados por 12 semanas. Resultados: Após 12 semanas de tratamento, o peso corporal, índice de massa corporal (IMC), relação cintura-quadril, HbA1c, FPG, glicose pós-prandial, ALT, AST, γ-GT e proteína C-reativa foram significativamente reduzidos, e a relação AST/ALT e a adiponectina aumentaram marcadamente nos dois grupos. O IMC, relação cintura-quadril, glicose pós-prandial, ALT, AST, γ-GT e proteína C-reativa foram marcadamente menores, e a relação AST/ALT e a adiponectina foram dramaticamente mais altas no grupo tratado com exenatide do que no grupo tratado com metformina. Conclusão: Comparado com a metformina, o exenatide controla melhor a glicose sérica, reduz o peso corporal e melhora as enzimas hepáticas, atenuando a DHGNA em pacientes com T2DM de ocorrência concomitante com a DHGNA. Arq Bras Endocrinol Metab. 2013;57(9):702-8 Descritores Exenatide; metformina; doença hepática gordurosa não alcoólica; diabetes melito tipo 2

No abstract

No abstract

BACKGROUND AND PURPOSETwo peptide agonists of the glucagon-like peptide-1 (GLP-1) receptor, exenatide and GLP-1 itself, exert anti-hypersensitive effects in neuropathic, cancer and diabetic pain. In this study, we have assessed the anti-allodynic and anti-hyperalgesic effects of the non-peptide agonist WB4-24 in inflammatory nociception and the possible involvement of microglial β-endorphin and pro-inflammatory cytokines. EXPERIMENTAL APPROACHWe used rat models of inflammatory nociception induced by formalin, carrageenan or complete Freund's adjuvant (CFA), to test mechanical allodynia and thermal hyperalgesia. Expression of β-endorphin and pro-inflammatory cytokines was measured using real-time quantitative PCR and fluorescent immunoassays. KEY RESULTSWB4-24 displaced the specific binding of exendin (9-39) in microglia. Single intrathecal injection of WB4-24 (0.3, 1, 3, 10, 30 and 100 μg) exerted dose-dependent, specific, anti-hypersensitive effects in acute and chronic inflammatory nociception induced by formalin, carrageenan and CFA, with a maximal inhibition of 60-80%. Spinal WB4-24 was not effective in altering nociceptive pain. Subcutaneous injection of WB4-24 was also antinociceptive in CFA-treated rats. WB4-24 evoked β-endorphin release but did not inhibit expression of pro-inflammatory cytokines in either the spinal cord of CFA-treated rats or cultured microglia stimulated by LPS. WB4-24 anti-allodynia was prevented by a microglial inhibitor, β-endorphin antiserum and a μ-opioid receptor antagonist. CONCLUSIONS AND IMPLICATIONSOur results suggest that WB4-24 inhibits inflammatory nociception by releasing analgesic β-endorphin rather than inhibiting the expression of proalgesic pro-inflammatory cytokines in spinal microglia, and that the spinal GLP-1 receptor is a potential target molecule for the treatment of pain hypersensitivity including inflammatory nociception.