Problems with myelin theory

Richard Hall rhall at uvi.edu
Fri Feb 13 06:02:41 EST 1998


At 8:14 PM -0500 2/12/98, Jeremy Leipzig wrote:
>Several neuroscience textbooks cite the ability of myelin to increase
>the capacitance [snip]
>I am confused by this claim for the following reasons:
>    1) There is no myelin in the Nodes of Ranvier where the
>voltage-gated ion channels are located.

That is consistent with the formation of action potentials at the nodes.
High membrane capacitance is necessary if axonal currents are to depolarize
Em to threshold.  The voltage gated channels would be of no value if it
were impossible to charge and discharge the membrane capacitors.

rlh


Richard Hall
Comparative Animal Physiologist
Division of Sciences and Mathematics
University of the Virgin Islands
St. Thomas, USVI  00802

809-693-1386
rhall at uvi.edu





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