excitotoksisuuden

Excitotoxicity refers to the pathological process by which nerve cells are damaged or killed by excessive stimulation by neurotransmitters. While glutamate is the most common excitatory neurotransmitter in the brain and is essential for normal brain function, including learning and memory, overstimulation by glutamate can lead to neuronal death. This occurs when glutamate receptors on the surface of neurons are excessively activated, leading to a prolonged influx of calcium ions into the cell.

This excessive calcium influx triggers a cascade of damaging intracellular events. These include the activation of enzymes that degrade cellular components, the production of reactive oxygen species (free radicals) that damage cell structures, and mitochondrial dysfunction, which impairs energy production and can lead to apoptosis (programmed cell death).

Excitotoxicity is implicated in a range of neurological conditions and injuries. These include stroke, traumatic brain injury, epilepsy, and neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis (ALS). In stroke and traumatic brain injury, for instance, a surge of glutamate is released due to the disruption of normal blood supply or physical trauma, overwhelming the brain's regulatory mechanisms and leading to widespread neuronal damage. Research into understanding and mitigating excitotoxicity is a significant area in neuroscience, with potential therapeutic targets focusing on blocking glutamate receptors or reducing glutamate release.