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Introduction: The SCALP block is an important regional anesthesia method. In this study, we analyzed the SCALP block model for the first time in a rat model. Materials and Methods: In this study, 16 rats were divided into four different groups. Six nerve blocks were planned in both halves of the skull for the SCALP block, and three entry points were determined for each. Bupivacaine (Marcaine, AstraZeneca) 0.5 mg/kg was injected in the "low-dose" group, 1 mg/kg in the "medium-dose" group, 2 mg/kg in the "high-dose" group, and 4 mg/kg in the "very high-dose" group. A midline fronto-occipital incision was made, and a craniectomy was performed. At 0, 30, 60, 90, and 120 minutes after the surgical procedure, the rats were evaluated using the Rat Grimace Scale, and their pain scores were evaluated. At the end of 2 hours, the rats were sacrificed, blood samples were taken, and methemoglobin levels were studied. Finally, a comparative analysis was performed between the four groups. Results: In 30, 60, 90, and 120 minutes after surgery, the differences between the grimace scores between low-dose and medium-dose and high-dose and low-dose groups were statistically significant (p<0.001). There was no significant difference between the high-dose and very high-dose groups regarding the grimace scale (p>0.05). Methemoglobin levels were statistically significantly higher after SCALP block with a very high dose of bupivacaine than blockade with a high dose of bupivacaine (p<0.001). Therefore, very high-dose bupivacaine injection was not superior to high-dose bupivacaine injection in pain control. In addition, very high doses of bupivacaine injection can be associated with increased morbidity and mortality due to increased methemoglobin levels. Conclusion: In this SCALP block technique described in rats, a 2 mg/kg bupivacaine injection can be considered an appropriate dosage for both safety and efficacy.

Background: In radiotherapy (RT) exposure area, normal tissues are also affected that may cause serious complications in the patients. This study aimed to evaluate Annona muricata’s radioprotective effects on sciatic nerve injury due to ionizing radiation (IR). Methods and Results: 32 adult female Wistar albino rats separated into 4 equal groups; Control (C), Annona muricata leaf extracts (AME), radiation (RAD), radiation and Annona muricata leaf extracts (AME+RAD). In groups AME and AME+RAD, Annona muricata leaf extracts were administered at a dose of 300 mg/kg for the first day and 50 mg/kg everyday for following one week intraperitoneally. In RAD and AME+RAD, rats were exposed to a single dose of 20 Gray IR to their right legs. All the subjects were sacrified at the end of the first month. Oxidative stress biochemical parameters (SOD, CAT and GPx) from blood samples were analyzed. Right sciatic nerves extracted and histomorphology evaluated. Statistically significant vasculature, degenerative and necrotic changes were observed in RAD, compared to C and AME (p<0,01). Swelling in myelin sheath was predominantly seen in RAD. Alterations in the level of CAT (p<0,01), SOD (p<0,01) and GPx (p<0,05) in AME+RAD group compared to RAD group were found to be statistically significant.Conclusion: Our study unveiled that AM could have a potential of biochemically and histomorphology healing on sciatic nerve injury due to ionizing radiation.