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

Objectives: Access to maternal and neonatal care services (MNCS) is an important goal of health policy in developing countries. In this study, we proposed a 3-level hierarchical location-allocation model to maximize the coverage of MNCS providers in Iran. Methods: First, the necessary criteria for designing an MNCS network were explored. Birth data, including gestational age and birth weight, were collected from the data bank of the Iranian Maternal and Neonatal Network national registry based on 3 service levels (I, II, and III). Vehicular travel times between the points of demand and MNCS providers were considered. Alternative MNCS were mapped in some cities to reduce access difficulties. Results: It was found that 130, 121, and 86 MNCS providers were needed to respond to level I, II, and III demands, respectively, in 373 cities. Service level III was not available in 39 cities within the determined travel time, which led to an increased average travel time of 173 minutes to the nearest MNCS provider. Conclusions This study revealed inequalities in the distribution of MNCS providers. Management of the distribution of MNCS providers can be used to enhance spatial access to health services and reduce the risk of neonatal mortality and morbidity. This method may provide a sustainable healthcare solution at the policy and decision-making level for regional, or even universal, healthcare networks.