Agmatine Mitigates Diabetes-Related Memory Loss in Female Mice by Targeting I(2)/I(3) Imidazoline Receptors and Enhancing Brain Antioxidant Defenses.

Cognitive decline is a common complication of diabetes mellitus, driven in part by oxidative stress and impaired glucose-insulin homeostasis. This study examined the neuroprotective effects of agmatine (200 mg/kg intraperitoneally) in female BALB/c diabetic mice. Several receptor pathways were examined using commercially available antagonists. Behavioral performance was evaluated using the novel object recognition test. Metabolic parameters, such as glucose and insulin levels, as well as antioxidants, including catalase (CAT), superoxide dismutase (SOD), and glutathione (GSH), were measured in blood and brain tissue. The diabetic mice exhibited impaired recognition memory (discrimination index = 0.08), hyperglycemia (24.3 mmol/L), decreased insulin levels (38.4 µU/mL), and diminished antioxidant defenses (CAT: 75.4 U/g tissue, SOD: 32.6 U/g tissue, and GSH: 8.3 mmol/g tissue). Agmatine treatment improved cognitive function and reversed the biochemical alterations. However, these effects were reduced when agmatine was co-administered with imidazoline I(2)/I(3) receptor antagonists. Correlation analysis revealed that cognitive performance positively correlated with antioxidant enzyme levels and insulin levels and negatively correlated with glucose concentrations. Strong intercorrelations among CAT, SOD, and GSH levels suggest a coordinated antioxidant response. Overall, these results imply that agmatine's neuroprotective effects are partially mediated by modulation of the oxidative balance and glucose-insulin regulation via imidazoline receptors.