Question

The death of neurons following a stroke is caused by?

1) over-stimulation of nerve cells by abnormally high levels of glutamate
2) neuronal firing produced by compression
3) interruption of glycogen delivery to the cell
4) enhanced release of the inhibitory transmitter GABA
5) loss of oxygen radicals

Answer 1

During a stroke, the death of neurons is caused by the interruption of blood flow to the brain, leading to a deprivation of oxygen and glucose supply. This interruption causes the depolarization of neurons' membranes, leading to the entry of excess calcium ions. The excess calcium triggers excitotoxic mechanisms, ultimately resulting in neuronal death.

Step-by-step explanation:

During a stroke, the blood flow to part of the brain is disrupted either due to a blockage in a blood vessel feeding the brain (ischemic stroke) or due to a rupture in one of these vessels (hemorrhagic stroke). The interruption of the blood flow leads to a deprivation of oxygen and glucose supply to the affected neurons. This lack of energy causes depolarization of the neurons' membranes, leading to an influx of calcium ions when exposed to the neurotransmitter glutamate. The excess calcium entry then triggers excitotoxic molecular mechanisms, ultimately resulting in neuronal death.