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:
“Racism is an ism to which everyone in the world today is exposed; for or against, we must take sides. And the history of the future will differ according to the decision which we make.”
—Ruth Benedict (1887–1948)
“A great proportion of the inhabitants of the Cape are always thus abroad about their teaming on some ocean highway or other, and the history of one of their ordinary trips would cast the Argonautic expedition into the shade.”
—Henry David Thoreau (1817–1862)
“The myth of independence from the mother is abandoned in mid- life as women learn new routes around the mother—both the mother without and the mother within. A mid-life daughter may reengage with a mother or put new controls on care and set limits to love. But whatever she does, her child’s history is never finished.”
—Terri Apter (20th century)