Antidepressant effect of taurine in diabetic rats

Clinical and preclinical studies have shown that diabetic individuals present more depressive behaviors than non-diabetic individuals. Taurine, one of the most abundant free amino acids in the central nervous system, modulates a variety of biological functions and acts as an agonist at GABAA receptors. Our objective was to assess the antidepressant effect of taurine in diabetic rats. Additionally, we studied the effect of taurine on weight gain, water and food intake, and blood glucose levels in diabetic and non-diabetic rats. Male Wistar rats were divided into control (CTR) and streptozotocin-induced diabetic (STZ) groups and were administered daily 0, 25, 50 or 100 mg/kg of taurine (n = 10 per subgroup) intraperitoneally. After 28 days of treatment, the animals were exposed to the forced swimming test, and their behaviors were recorded. Weight gain, water and food intake, and blood glucose levels were measured weekly. Our results showed that STZ rats had a higher immobility duration than CTR rats, and taurine decreased this depressive-like behavior in STZ rats at doses of 25 and 100 mg/kg. Both of these doses of taurine also decreased water intake and improved weight gain in STZ rats. All doses of taurine decreased the water intake in CTR rats. Taurine, at a dose of 100 mg/kg, decreased food intake and blood glucose levels in STZ rats. Because taurine is a GABA agonist and both amino acids are lower in the plasma of diabetic and depressive individuals, we hypothesize that taurine may represent a new adjuvant drug for the treatment of depression in diabetic individuals.