I believe it was Peter Mitchell who worked out the mechanism of
oxidative phosphorylation. It involves a proton conductance through a
membrane, which overcomes the problems with the charge on the proton.
The reason I bring this up is that there is a problem with neural
spines--the spine neck is quite narrow, and does not allow ionic flow
between the spine and the dendrite.
However, my taking a course from Harold Morowitz on metabolism begins to
provide some insight here. He keeps emphasizing the importance of static
cell structure to how the cell operates. (He's taken metazoans down
nearly to absolute zero and then revived them--which you could not do if
persistent dynamics were necessary to life.) The problem with the spine
neck would go away if there were some sort of biological structure that
supported the necessary ion flow. I.e., ion wires through the neck...
Has anyone looked to see if microtubules supported ionic conductance?
That would also start to provide some insight into their role in the
protistan neuroskeleton. Based on structure, they might even function as
some sort of coaxial cable.
Internet: herwin at gmu.edu