http://alanrendall.wordpress.com/2009/02/22/migrating-ion-channels-part-2/ A mathematician thinks aloud Thu, 09 May 2013 07:10:22 +0000 hourly 1 http://wordpress.com/ http://alanrendall.wordpress.com/2009/02/22/migrating-ion-channels-part-2/#comment-126 Mon, 06 Apr 2009 07:35:39 +0000 http://alanrendall.wordpress.com/?p=397#comment-126 I now noticed that the original post contained an error and an omission.The error was to claim the the action of the sodium-potassium pump is charge neutral. In fact the pump transfers three sodium ions and only two potassium ions in each cycle. This does not have a very large effect on the membrane potential since the resulting charge transfer is compensated by the influence of mobile chloride ions. These facts have been known for a long time – see for instance the Nobel lecture of Jens Skou, the discoverer of these pumps. The omission was that the parts of the cycle I described lead to a net change in the sodium and potassium concentrations. These must be reversed by the sodium-potassium pumps in order to restore the original state.

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