Insulin and the Brain
By Yecenia Arellano
Hello! We are a group of UCSD student taking Cogs 163: Metabolic Brain Disorders. We will be documenting our journey through the quarter as we learn what secrets our metabolism can unlock about our brain!
First off, many do not realize that there is a connection between insulin and the brain because insulin is regarded as more of a gut hormone. It is widely known that insulin controls blood glucose levels and diabetes is a disease that arises due to irregular insulin secretion and responses. However, insulin has been found to act within the brain as well. Insulin response is now being studied in terms of its effects in people with degenerative brain diseases.
How is insulin being regulated by the brain? Your autonomic nervous system has direct connection with the pancreas via the islets. If your Parasympathetic nervous system is active you body will release more insulin if you body is in sympathetic mode your body will stop insulin secretion. These islets which are responsible for insulin secretion consist mostly of β-cells that are responsible for secreting insulin and amylin in order control blood glucose levels. Then there are also α-cells which secrete glucagon inorder to stimulate release of glucose into the blood stream. These two types of cells found within the islets seem to be the most important so far. As we continue to learn about the workings of insulin and the brain δ-cells, ε-cells, and F-cells that are also found within the islets will surely play a more complicated role.
Not only is insulin regulated through these autonomic nervous system responses but also other cephalic responses. Specifically, the information that your brain receives from your senses can affect inuslin secretion. They were able to study this in rats where they found insulin production increased in rats who were just presented with food. What does this mean? Your body is constantly trying to regulate insulin by various pathways in order maintain homeostasis!
What happens when your become insulin resistant? In an essence this is type 2 diabetes. Your blood glucose levels are not being regulated properly even though there is insulin present in the blood. The body is not as responsive to insulin. Although we can control peripheral insulin and it effects through medication, what about centrally? Experiencing insulin resistance within the brain has been correlated to contribute to degenerative brain diseases. Perhaps there can be a new form of treatment taking into account the information of insulin.