Neuronic system inside neurons: molecular biology and biophysics of neuronal microtubules

Abstract

Neurons are highly specialized cells that input, process, store and output information. Interneuronal communication is achieved in four basic ways: (i) Ca 2+ evoked exocytosis with chemical neurotransmission, (ii) gap junction electrotonic coupling, (iii) secretion of neurosteroids, nitric oxide and derivatives of the arachidonic acid acting in paracrine manner, and (iv) cellular adhesive protein interactions with scaffold protein reorganization. Central structure integrating these anisomorphic signals is the neuronal cytoskeleton that is considered to be both sensitive to the local electromagnetic field and prone to intense biochemical modification. With the use of biophysical modeling we have shown that the local electromagnetic field interaction with neuronal microtubules could result in formation of dissipationless waves (solitons) of tubulin tail conformational states that propagate along the microtubule outer surface. Soliton collisions may subserve the function of elementary computational gates and the output of the computation performed by the microtubules may be achieved by the energase action of the tubulin tails that control microtubule-associated protein and motor protein attachment/detachment on the microtubule outer surface. Biomedical Reviews 2004; 15: 67-75.