Biographical Memoirs Volume 70 (1996) / Chapter Skim
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Kenneth Stewart Cole
Kenneth Stewart Cole
Pages 24-45
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experimental approaches, he macle major contributions to our unclerstancling of the surface membranes of many types of cells, en c! especially of the changes undergone by the electrical properties of the membranes of excitable cells when activated.
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by, Irving Langmuir, whose famous work on surface f;Ims at an air-water interface may well have been one of the origins of Cole's interest in the surface membranes of living cells.
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to biology after spencling the next summer at the Marine Biological Laboratory at Woocis Hole on Cape CocI, Massachusetts, where he worker! on heat procluction by the eggs of the sea urchin Arbacia uncler C.G.
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l. Curtis, who had previously worked with Fricke and was thus familiar with alternating current methods of investigating the electrical properties of biological objects.
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resistance of the membrane of the squid giant nerve fibre in the resting state (a quantity that conic! not be cleterminec!
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Katz hac! clone in 1947 establishing that the action potential is generated by sodium ions moving down their concentration gradient.
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. surface membrane of these cells, in close agreement with more recent determinations, he took the clielectric con stant of the lipic!
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the linear, passive electrical properties of cell membranes. At first, in place of the alternating current bridge user!
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Cole's next contribution (7~* was a theoretical treatment of the bulk electrical properties of a cell suspension in which the surface of the cell hac!
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his attention from cell suspensions to excitable tissues, mostly the fresh-water alga Nitella which has long cylindrical cells capable of propagating a Tong-lasting (approximately one second) action potential, en c!
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many millimetres, a substantial fraction of the current flows through the surface membrane even at low frequencies or with direct current, en c! the membrane resistance can be measurer!
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en c! then in the giant nerve fibre of the squic!
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was much larger than the resting potential (insicle about 45 mV negative to external solution) so that the internal potential became positive at the peak of the action potential by some
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was clue to entry of sodium ions moving uncler the influence of their concentration difference. The first was that they user!
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a relation, sometimes known as Cole's theorem, by which they obtainer! current density Im at membrane potential Vm from the measurec!
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This was the carbon filament lamp, in which the electrical resistance fails with rise of temperature so that when a constant voltage is applier!
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at zero by the feedback circuit. The result was an action potential in which the time course was not complicated by longitudinal current flow, however, it was not very different from an ordinary propagates!
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at that meeting (which macle soclium current an instantaneous function of membrane potential) whereas we attributer!
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by their extensive experimental en c! theoretical investigations that these irregularities were instrumental artifacts, arising only when the surface resistance of the long internal electrocle was not Tow enough to ensure that at each instant the potential difference across the fibre membrane was uniform over the length from which the current was being recorclecI.
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44 B I O G RA P H I C A L EMOIRS fit within the range of membrane potential that occurs in a living fibre. Cole's last major contribution was his book Membranes, ions and impulses (93)
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From page 45... ...
& Huxley, A.F. 1945 Resting and action potentials in single nerve fibres.
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