STItllLATED NEURITE FORMATION IN VITRO

In this chapter the role of endogenous and applied electric fields in growth and regeneration of nerve tissue are explored. Alt­ hough nerve tissue uses electricity for communication with and between target tissue. imposition of external electric fields by applying direct current or using Helmholtz coils to induce current have been shown to affect various processes. Such processes include stimulation of neurite outgrowth (which may be directionally-oriented). increased neuronal survival. modification of cell shape and redistribution of membrane receptors. Application of such fields to nerve tissue growing in culture dishes permits the investigation of the mechanisms under­ lying these events. While these mechanisms are poorly understood. electrophoresis of membrane components. and changes in ion concentra­ tion extracellularly and intracellularly have been implicated. To this end. the importance of calcium ions in the transduction of electric Signals to growth and regenerative processes will be discussed.