Transmissió de potencials d'acció basada en la propagació de camps elèctrics intra-membrana
- Autores: Albert Martí Edo
- Directores de la Tesis: Jordi Madrenas Boadas (dir. tes.)
- Lectura: En la Universitat Politècnica de Catalunya (UPC) ( España ) en 2017
- Idioma: español
- Tribunal Calificador de la Tesis: Josep Valls Solé (presid.), Francesc Xavier Rosell Ferrer (secret.), Jordi Hernández Borrell (voc.)
- Programa de doctorado: Programa Oficial de Doctorado en Ingeniería Electrónica
- Materias:
- Enlaces
- Tesis en acceso abierto en: TDX
- Resumen
Current theories and mechanisms of nerve impulse propagation inside neurons do not give a satisfactory explanation to the nanoscale processes that occur inside the membrane. Propagation at the dendritic zones, and at the myelinated and unmyelinated axons, presents effects and events that, despite numerical calculations of current models fit with biological results obtained with macroscopic measurements, are far from giving an explanation to the real operation of biological mechanisms and to the effects and behaviors that the involved biological elements support.
Current biological knowledge on the structure and behavior of biological membranes, as well as on the structure and function of voltage-regulated ion channels, allows us to consider alternatives to existing propagation mechanisms, giving explanation to the effects and behavior from both nanoscale and macroscopic level.
This theoretical study proposes intra-membrane electric field propagation as a feasible propagation mechanism capable to explain both macroscopic and nanometric effects.
With current theories and mechanisms, generation, propagation and regeneration of the nerve impulse is based on the action potential propagation effect. The action potential can be defined as the temporal imbalance that affects the membrane potential during nerve impulse propagation, as a consequence of ion channel opening.
Progress on the neural membrane biological structure knowledge has allowed to propose a new hypothesis on the action potential operation. Besides the membrane potential variation, the electric charge that crosses the membrane generates an electric field that propagates inside the cell membrane, activating the closer ionic channels. This mechanism gives an explanation compatible with existing biological components and with other effects hard to explain with the standard current mechanisms. In addition, the proposed intra-membrane electric field propagation mechanism allows for a different explanation of the action potential evolution, as well as ion traffic level more in line with the capabilities of the biological reality, both on the ion traffic level and energy consumption.
The proposed mechanism allows to explain the so-called saltatory action potential propagation on myelinated axons, and to apply the saltatory propagation to unmyelinated axons. In the latter, as short-distance steps; in the former, as long-distance jumps, also giving a coherent answer to the constant-time propagation independent of the distance between nodes of Ranvier.
The proposed mechanism suggests that the effects the action potential presents are more the result of a charge displacement inside sodium and potassium channels than a current that crosses ion channels.
An important factor to consider in this mechanism is the energy consumption minimization, a fundamental biological premise for maximum optimization of process operation.
Keywords: Intra-Membrane Electric Fields, Neural Membrane, Voltage-Gated Ion Channels, Nanometric Behavior, Macroscopic Behavior, Action Potential, Saltatory Propagation, Unmyelinated Axons, Myelinated Axons.
