Deterioration of Ion Gradients

Inadequate energy supply leads to deterioration of ion gradients. Anoxic depolarization (equilibration of intracellular and extracellular ions) causes potassium to leave the cell and sodium, chloride, and calcium ions to enter. It also stimulates the massive release of the amino acids glutamate and aspartate, excitatory neurotransmitters in the brain.

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Glutamate further activates sodium and calcium ion channels in the neuron membrane.

As sodium and calcium ions rapidly accumulate within the cells, accompanied by an inflow of water, cytotoxic edema causes rapid swelling of neurons and glia.

Activation of calcium channels results in further influx of calcium into the cell. One of the most intensely studied calcium channels is the N-methyl-D aspartate (NMDA) channel.

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