Effect of sodium valproate and docosahexaenoic acid on pain in rats

Introduction: Analgesics are commonly prescribed medications used to alleviate pain of various aetiologies without affecting the patient’s consciousness. They interfere with the transmission of pain signals. A commonly used antiepileptic drug, sodium valproate has been used in various non-epileptic conditions like migraine prophylaxis and in the treatment of bipolar disorder because of the multiple mechanisms by which it acts. Docosahexanoic Acid (DHA), an omega 3 fatty acid, is known to possess analgesic activity. We planned a study to assess the effect of sodium valproate alone and in combination with DHA in rat models of pain. Aim: To evaluate the analgesic activity of sodium valproate and DHA supplementation using various experimental models in albino Wistar rats. Materials and Methods: For analgesic activity, A total of 48 adult Wistar albino rats were divided into eight groups of six rats each. Group I was control (distil water 1 ml/kg), Group II received intraperitoneal injection of tramadol (10 mg/kg), Group III, IV, V were injected intraperitoneal sodium valproate 100, 200, 400 mg/kg with distil water respectively and Group VI, VII, VIII were given sodium valproate 100, 200, 400 mg/kg plus DHA 300 mg/kg (intraperitoneal) respectively. Analgesic activity was assessed using hot plate, tail flick and acetic acid writhing models. Results: We found that sodium valproate at higher doses (400 mg/kg) used either alone along with DHA (300 mg/kg) showed statistically significant analgesic activity in comparison to control in various experimental models for assessing pain. Conclusion: Combination of sodium valproate along with DHA has shown promising analgesic activity.