What is the role of cerebral ischemia in the pathogenesis of stroke?

Updated: May 27, 2020
  • Author: Edward C Jauch, MD, MS, FAHA, FACEP; Chief Editor: Helmi L Lutsep, MD  more...
  • Print
Answer

Cerebral ischemia impairs the normal sodium-calcium exchange protein also found on cell plasma membranes. The resulting influx of calcium leads to the release of a number of neurotransmitters, including large quantities of glutamate, which in turn activates N -methyl-D-aspartate (NMDA) and other excitatory receptors on other neurons.

These neurons then become depolarized, causing further calcium influx, further glutamate release, and local amplification of the initial ischemic insult. This massive calcium influx also activates various degradative enzymes, leading to the destruction of the cell membrane and other essential neuronal structures. [11] Free radicals, arachidonic acid, and nitric oxide are generated by this process, which leads to further neuronal damage.

Ischemia also directly results in dysfunction of the cerebral vasculature, with breakdown of the blood-brain barrier occurring within 4-6 hours after infarction. Following the barrier’s breakdown, proteins and water flood into the extracellular space, leading to vasogenic edema. This produces greater levels of brain swelling and mass effect that peak at 3-5 days and resolve over the next several weeks with resorption of water and proteins. [12, 13]


Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!