|Current Pathways and Electrophysiology|
Current Pathways and Electrophysiology
Bioelectricity is conducted through five main components that may be found in any vascularized part of the body.
1. Insulating walls of blood vessels
2. Conducting intravascular plasma
3. Insulating tissue matrix (possibly including lymph vessels)
4. Conducting interstitial fluid
5. Transcapillary electrical junctions for redox reactions
A relatively higher electrical resistance is present in the walls of large blood vessels and a relatively lower resistance in plasma and interstitial fluids, giving rise to a voltage gradient. The vessel walls in this bioelectrical circuit act as electrically conducting, insulating cables that carry plasma (the conducting media) and separate it from the surrounding conducting media (the interstitial fluid) except at its transcapillary junctions (the naturally occurring electrodes in the bioelectric circuit).
The capillary cell membranes act as naturally charged electrodes that allow ions to move through the cells via gates and vesicles. Additional ions flow between the cells through pores. This local ion flow stops when excess electrons cross enzyme bridges in the capillary walls, closing the pores and gates and thereby closing the local circuit. This occurrence creates a long distance bioelectrical circuit in which the ions flow. The capillary cell membranes, therefore appear to be the key component in switching from local ion flow across the capillary membranes to long distance ion flow down the capillary walls.
An accumulation of charge (excess electrons) can be generated by soft tissue injury or even normal muscle use. The accumulation of charge may constrict arterial capillaries, switching the current on. However, venous capillaries do not constrict in an electrical field; therefore, ions and charged cells (e.g. neutrophils) can migrate through the pores of a leaky venous capillary near the injury. Because the polarity of the electrical potential from an injury changes, charged cells and ions necessary for healing may ebb and flow as changes take place in the electrical insulation properties of the capillary membranes.
A direct current (DC) system operates within the nerve fiber similar to the way a semiconductor functions. In a semiconductor small amounts of electrical current are transmitted via positive and negative charges through a crystal lattice. When a stimulus such as trauma, amputation, anesthesia or microcurrent is applied to living tissue, the surface potentials change. Only two seconds after trauma is invoked, DC potentials progress up the neuraxis to the cranium. This activity suggests that a biologic model of a semiconductor system transmits data regarding injury and that the change in surface potential is a record of the injury data transmitted.
The DC semiconductor system is composed of Schwann cell sheaths in the periphery, satellite cells in the dorsal root ganglion, and glial cells in the CNS.
Calcium acts like a semiconductor thus is stimulated with biphasic as well as monophasic current. Traveling wave depolarization where a group of cells stimulate adjacent cells creates a current pathway allowing microcurrent to penetrate through the GSR. Greater effectiveness has been shown with higher voltages ie. +/- 37 volts.
Berridge, M. The molecular basis of communication within the cell. Sci. Am. 253:142-150; 1985.
Cheng, N., The effects of electric currents on ATP Generation, Protein Synthesis, and membrane transport in rat skin. Orth Surg. 1982
Gensler. W.: Bioelectric potentials and their relation to growth in higher plants. Ann. N.Y. Acad. Scl. 238:280. 1974.
Harrington, D. B.. and Becker. R. O.: Electrical stimulation of RNA and protein synthesis in the frog erylhrocyte. Exp. Cell Res. 76:95. 1973.
Heffernan, M. (1996). Comparative effects of microcurrent stimulation on EEG spectrum and correlation dimension. Integrative Physiology and Behavioral Science. 31 (3):202-209.
Heffernan, M. (1996b). Measurement of electromagnetic fields in the healing response. Epress, pp 1-6.
Luben, R.A. (1991). Effects of low-energy electromagnetic fields (pulsed and dc) on membrane signal transduction processes in biological systems. Health Physics. 61(1): 15-28.
McClanahan, B. J.; Phillips, R. D. The influence of electric field exposure on bone growth and fracture repair in rats. Bioelec-tromagnetics 4:11-19; 1983.
Pilla, A. A. Electrochemical information transfer at cell surfaces and junctions--application to the study and manipulation of cell regulation. In: Keyzer, H.; Gutman, F. Bioelectro-chemistry. New York: Plenum Publishing; 1980:353-396.
Schmukler, R.; Pilla, A. A. A transient impedance approach to nonfaradaic electrochemical kinetics at living cell membranes. J. Electrochem. Soc. 129:526-528; 1982.
Shamos. M. H., and Layinc. L. S.: Piezoelectricity as a fundamental property of biological tissues. Nature 213:267, 1967.
Witt. H. T.. Schlodder, E., and Graber. P.: Membrane-bound ATP synthesis generated by an external electrical field. FEBS Left. 69:272, 1976.