Background & Objective: It is reported that acute forced swimming stress induces analgesia immediately, and chronic stress induces hyperalgesia. Whereas in response to nociceptive stimulation, small-diameter C-fibers of the excitatory system in the dorsal horn of the spinal cord are activated, therefore, in the present study, the effects of C-fiber lesion in stress and dexamethasone-induced analgesia and hyperalgesia in acute and chronic forms were investigated using Tail-Flick test. Methods: Adults Wistar male rats (180-200 g) were assigned into three groups (n=7): C-normal (intact C-fibers), sham (received capsaicin vehicle at neonate stage) and C-lesion (received capsaicin at neonate stage). Forced swim stress (10 min/day) in water (18±1 ºC) was considered as acute stress and repeated daily forced swim stress as chronic stress, also single-dose of dexamethasone (2 mg/kg, i.p.) was considered as acute dexamethasone and repeated for three days as chronic dexamethasone. Neonatal capsaicin treatment was used for C-fibers depletion. The nociceptive thermal threshold was assessed using Tail-Flick test. Results: In C-lesion group, thermal pain sensitivity was reduced (P<0.001). Acute stress in C-normal group, reduced pain (P<0.001) and in C-lesion group, it caused deeper antinociception in Tail-Flick (P<0.001). Chronic stress and acute-chronic dexamethasone in C-normal group, created hyperalgesia (P<0.001) and induced analgesia in C-lesion groups (P<0.01). Conclusion: It seems that presence of C-fiber is so important in thermal pain transmission in Tail-Flick test; therefore, C-fiber lesion, reduces pain sensitivity (analgesia), increases antinociception effects of acute stress, decreases hyperalgesia of chronic-stress and acute-chronic dexamethasone
Analgesia ; Hyperalgesia

Diabetes mellitus is a common metabolic disease with considerable morbidity and mortality. Untreated or improperly-treated diabetes can be associated with several long-term complications that necessitate an effective way to manage diabetes. Due to the side effects of synthetic glucose-lowering agents, alternative therapeutic modalities such as medicinal plants have attracted notable attention. Teucrium polium L. is a medicinal herb with antioxidant, antinociceptive, anti-inflammatory, hypolipidemic, hepatoprotective, and hypoglycemic properties. In vitro and in vivo studies have been conducted to characterize the anti-diabetic properties of Teucrium polium L. and its bioactive compounds. We conducted a literature study using Scopus, PubMed, and Google Scholar including the keywords 'diabetes' and 'Teucrium polium'. We also scanned all the references cited by the retrieved articles. According to this review, Teucrium polium administration displayed anti-diabetic effects by targeting different mechanisms and pathways, such as enhancement of insulin secretion and insulin level, improvement of oxidative damage, regeneration of pancreatic β-cells, and promotion of glucose uptake in muscle tissues by increasing GLUT-4 translocation as well as inhibiting α-amylase activity. Although Teucrium polium has been widely regarded as a traditional method, the pharmacological studies on anti-diabetic effects are not sufficient, most studies are either in-vivo or in-vitro. The preclinical and clinical studies are further required to confirm the efficacy of Teucrium polium.