Objective: The research was designed to assess the consequences of Azadirachta indica aqueous leaf extract (AILE) on neuropathic pain in Wister rats and the role of the ATP-dependent potassium channel (KATP) as an underlying mechanism. Materials and Methods: This experimental layout was conducted on Wistar rats (n = 120) having 150 to 200 gm of body weight. On the foundation of the experimental design, rats were divided into group I (normal saline, 5 ml/kg/body weight) and group II (sham surgery and treatment with NS), group III [chronic constriction injury (CCI) in the sciatic nerve; and treated with NS], group IV (CCI and treated with AILE 400 mg/kg body weight), Group V (CCI, pretreated with Glibenclamide 15 mg/kg followed by treated with AILE 400 mg/kg). All the treatments were given once daily for a consecutive 21 days via the oral route, except Glibenclamide. Glibenclamide was given once through the intraperitoneal route on the day of the experiment. Results: Based on the neuropathic pain evaluation test, all groups were again sub-divided into subgroup “a” (walking tract analysis), “b” (cold tail immersion test), “c” (Von Frey test), and “d” (hot plate test). AILE showed a significantly higher sciatic functional index (p < 0.05) in walking track analysis, tail flick latency (p ≤ 0.05) in the cold tail immersion test, and paw withdrawal threshold (p ≤ 0.05) in the Von Frey test compared to CCI control. In addition, a nonsignificant difference in all these above-mentioned variables between the rats with CCI plus AILE and the CCI plus AILE plus glibenclamide group indicated that the KATP channel was not involved in the beneficial analgesic effects of AILE. Conclusions: The outcome of the present study indicates that AILE prevented worsening of neu¬ropathic pain after chronic constriction injury in the sciatic nerve of Wistar rats in which the KATP channel was not involved.

Background: In treatment of neuropathic pain, conventional analgesics showed various adverse effects. Spirulina platensis (Sp), a medicinal herb, shown to possess several beneficiary biological activities including analgesic, anti-inflammatory and anti-ulcerogenic potential. Objectives: To assess the effect of Sp on neuropathic pain in Wistar rats and also to assess the involvement of ATP sensitive potassium channel (KATP) as its possible underlying mechanism of action. Methods: For this experimental study 120 Wistar rats of both sexes (200±50 gm body weight) were grouped into control [normal saline (NS) 5 ml/kg/day], sham control [sham surgery + NS], CCI control [Chronic constriction injury to sciatic nerve (CCI) + NS], Sp experimental [CCI + Sp 400 mg/kg/day], Gli experimental [CCI + Sp (400 ml/kg/day) + glibenclamide (15 mg/kg)] groups. Sp and NS were administered orally once daily for consecutive 21 days and single dose of glibenclamide was given intraperitoneally. Then again on the basis of neuropathic pain evaluation tests, all the groups were subdivided into ‘a’ (for walking track analysis), ‘b’ (for cold tail immersion test), ‘c’ (for von Frey test), ‘d’ (for hot plate test). The statistical analysis was done by one-way ANOVA followed by Bonferroni post hoc test, where P£0.05 was considered as statistically significant. Results: In this study, Sp showed significantly (P£0.001) higher sciatic functional index, tail flick latency, paw withdrawal threshold and reaction time in Sp experimental rats compared to those of CCI control rats. In addition, there were significant (P£0.001) differences in the above-mentioned variables between rats of Sp experimental group and Gli experimental group. Conclusion: From the present study it could be concluded that, Spirulina platensis prevents the development of neuropathic pain in Wistar rats through opening of KATP channel. J Bngladesh Soc Physiol 2021;16(1): 1-10