Özet:

Alzheimer’s disease (AD) is the most common cause of dementia. The term of 'Type 3 diabetes' is constituted to point out the insulin deficiency and resistant in the brain of people with AD. In postmortem studies about AD, it has I detected that insulin receptors, insulin-like growth factor 1 and 2, insulin messenger ribonucleic acid are decreased in the brain. Insulin can pass through brain-blood-barrier, besides it can be synthesized by a group of neurons internally. Gene expression of insulin is present in mature and immature neurons of mammals. Insulin has important effects on regulation of energy metabolism of neurons and neuronal recovery. Decreased glucose uptake and adenosine triphosphate production in the case of insulin deficiency, leads to an impairment in neuronal homeostasis. Insulin can increase cognitive functions without changing plasma glucose and insulin levels when it was applied intranasally. Insulin and its sub-pathways will maintain its current importance about improvement and protection of cognitive functions