What metabolic mechanisms may allow essential brain function

What metabolic mechanisms may allow essential brain functions to continue after changes in blood flow.

Solution

The brain is the organ of body which utilizes maximum amount of energy per unit time and constantly performs biological functions. The brain is separated from the other parts of body by the means of presence of blood-brain-barrier which sieves the materials which are not meant to pass through the vasculature and enter the cephalic system. Since glucose is transported through the body by blood, brain also recieves this energy substrate from the blood. However, if there are changes in the rate of flow or amount of glucose in the blood, the supply of glucose might be interrupted and brain cells would rely upon other means of metabolism and energy generation. These mechanisms include primarily glycolysis but other means are also possible.

In situations where blood flow is interrupted, lactate can be the substrate of choice by the neuronal and non-neuronal brain cells for metabolism. Although lactate metabolism is not technically as efficient as glucose metabolism, but it represents the safest method of all which generates substantial amount of energy even under hypoxic conditions and helps the neurons to survive. Functional magnetic resonance imaging experiments have shown that absence of glucose as the primary metabolic source make the neurons less active and push them to utilize lactate as a preferred energy source.

Thus, this explanation describes that lactate metabolism might be the mechanism of choice if glucose is not available due to changes in blood flow towards the brain.