Role of microtubules in neuro-electrical transmission: a hypothesis

Unlike man-made electronic devices such as computers, the nervous system never suffers from “overheating” due to its massive neuro-electrical activities. This paper proposes a new hypothesis that neuronal microtubules (neuro-MTs), which are major structural components of axons and dendrites, are vacuum cylindrical nanotubes that can mediate electrical transmission with a unique form of quasi-superconductivity. It is speculated that hydrolysis of guanosine triphosphate catalyzed by the a-/ß-tubulin subunits would supply cellular energy to relocate electrons to form the conduction electrons inside neuro-MTs. Owing to the consecutive dipole ring structures of neuro-MTs, the moving speed of the conduction electrons inside neuro-MTs is expected to be very slow, and this feature would enable physiological neuro-electrical transmission with super-high energy efficiency. Further, the dipole ring structures of a neuro-MT would help terminate the electron conduction with high efficiency. The proposed neuro-MT-mediated electrical transmission offers a new mechanistic explanation for the saltatory conduction of action potentials along the axons. Lastly, it is speculated that owing to its unique consecutive dipole sheet structures, the myelin sheath which wraps around large axons and some dendrites, may functionally serve as an effective shield for the electromagnetic fields generated by the conduction electrons inside the axonal neuro-MTs.