History
Existence of potassium siphoning was first reported in 1966 study by Orkand et al. In the study, optic nerve of Necturus was dissected to document the long-distance movement of potassium after the nerve stimulation. Following the low frequency stimulation of .5 Hz at the retinal end of the dissected optic nerve, depolarization 1-2mV was measured at astrocytes at the opposite end of the nerve bundle, which was up to several millimeters from the electrode. With higher frequency stimulation, higher plateau of depolarization was observed. Therefore, they hypothesized that the potassium released to extracellular compartment during axonal activity entered and depolarized nearby astrocytes, where it was transported away by unfamiliar mechanism, which caused depolarization on astrocytes distant from site of stimulation. The proposed model was actually inappropriate since at the time neither gap junctions nor syncytium among glial cells were known ,and optic nerve of Necturus are unmyelinated, which means that potassium efflux occurred directly into the periaxonal extracellular space, where potassium ions in extracellular space would be directly absorbed into the abundant astrocytes around axons.
Read more about this topic: Potassium Spatial Buffering
Famous quotes containing the word history:
“The history of all Magazines shows plainly that those which have attained celebrity were indebted for it to articles similar in natureto Berenice—although, I grant you, far superior in style and execution. I say similar in nature. You ask me in what does this nature consist? In the ludicrous heightened into the grotesque: the fearful coloured into the horrible: the witty exaggerated into the burlesque: the singular wrought out into the strange and mystical.”
—Edgar Allan Poe (1809–1849)
“Every generation rewrites the past. In easy times history is more or less of an ornamental art, but in times of danger we are driven to the written record by a pressing need to find answers to the riddles of today.... In times of change and danger when there is a quicksand of fear under men’s reasoning, a sense of continuity with generations gone before can stretch like a lifeline across the scary present and get us past that idiot delusion of the exceptional Now that blocks good thinking.”
—John Dos Passos (1896–1970)
“A country grows in history not only because of the heroism of its troops on the field of battle, it grows also when it turns to justice and to right for the conservation of its interests.”
—Aristide Briand (1862–1932)