Diseases
In patients with Tuberous Sclerosis Complex (TSC), abnormalities occur in astrocyte, which leads to pathogenesis of neurological dysfunction in this disease. TSC is a multisystem genetic disease with mutation in either TSC1 or TSC2 gene. It results in disabling neurological symptoms such as mental retardation, autism, and seizures. Glial cells have important physiological roles of regulating neuronal excitability and preventing epilepsy. Astrocytes maintain homeostasis of excitatory substances, such as extracellular potassium, by immediate uptake through specific potassium channels and sodium potassium pumps. It is also regulated by potassium spatial buffering via astrocyte networks where astrocytes are coupled through gap junctions. Mutations in TSC1 or TSC2 gene often results in decreased expression of the astrocytic connexin protein, Cx43. With impairment in gap junction coupling between astrocytes, myriad of abnormalities in potassium buffering occurs which results in increased extracellular potassium concentration and may predispose to neuronal hyperexcitability and seizures. According to a study done on animal model, connexin43-deficient mice showed decreased threshold for the generation of epileptiform events. The study also demonstrated role of gap junction in accelerating potassium clearance, limiting potassium accumulation during neuronal firing, and relocating potassium concentrations.
Demyelinating Diseases of the central nervous system, such as Neuromyelitis Optica, often leads to molecular components of the panglial syncytium being compromised, which leads to blocking of potassium spatial buffering. Without mechanism of potassium buffering, potassium induced osmotic swelling of myelin occurs where myelins are destroyed and axonal salutatory conduction ceases.
Read more about this topic: Potassium Spatial Buffering
Famous quotes containing the word diseases:
“Arrogance, pedantry, and dogmatism ... the occupational diseases of those who spend their lives directing the intellects of the young.”
—Henry S. Canby (1878–1961)
“The fantasies inspired by TB in the last century, by cancer now, are responses to a disease thought to be intractable and capricious—that is, a disease not understood—in an era in which medicine’s central premise is that all diseases can be cured.”
—Susan Sontag (b. 1933)
“But what is quackery? It is commonly an attempt to cure the diseases of a man by addressing his body alone. There is need of a physician who shall minister to both soul and body at once, that is, to man. Now he falls between two stools.”
—Henry David Thoreau (1817–1862)