title: Propagation speed in myelinated nerve. I. Experimental dependence on external Na and on temperature.
abstract: Conduction speed (theta) in single myelinated Rana pipiens sciatic nerve fibers has been precisely measured using intracellular recording and on-line digital computer techniques. The dependence of relative speed on external Na concentration at 15 degrees C has been found to be ln(theta(1)/theta(2)) = 0.524 (+/-0.018) ln ([Na(+)](1)/[Na(+)](2)) + 0.003. Thus theta has very close to a square root dependence on [Na(+)](0) for these fibers. This experimental finding is not in complete agreement with a theoretical prediction based on a solution of the Hodgkin-Huxley (H.H.) equations. The effect of small temperature variations around 15 degrees C on theta has also been measured for Rana fibers in Ringer's solution. theta has close to an exponential dependence on T and a Q(10) of 2.95 has been estimated.
mesh_terms: D000818:Animals; D001001:Anura; D003201:Computers; D004558:Electric Stimulation; D007700:Kinetics; D008954:Models, Biological; D009431:Neural Conduction / Q000187:drug effects; D010477:Perfusion; D011894:Rana pipiens; D012584:Sciatic Nerve / Q000187:drug effects / Q000502:physiology*; D012964:Sodium / Q000494:pharmacology*; D013696:Temperature
chemical_list: D012964:Sodium