Insulin neuroprotection against oxidative stress involves increased antioxidant defenses and glucose metabolism

Brain cortex is highly enriched in insulin, insulin receptor (IR) and insulin-like growth factor-1 receptor (IGF-1R). Brain insulin may arise either from pancreatic (a) over cap -cells, being transported into central nervous system (CNS) through blood-brain barrier or area postrema, and/or from local de novo synthesis. Insulin regulates brain metabolism, neuronal growth and differentiation or neuromodulation. Recent hypothesis also suggest that insulin may have a neuroprotective role against stress conditions, namely oxidative stress, which may underlie the pathophysiology of neurodegenerative disorders and diabetic complications. Previously, we analysed the neuroprotection by insulin on neuronal dysfunction and death caused by oxidative stress in cortical neurons. Our results suggest that insulin neuroprotection may involve the stimulation of glucose metabolism and antioxidant defenses and the decrease in extracellular adenosine.