Other Nerve Regeneration Stimuli 51 Electrical Stimulation

Enhanced neural tissue regeneration with applied electrical stimulation has been documented over the past few decades (Borgens et al. 1979; McDevitt et al. 1987). In both the PNS and CNS, electrical fields have been shown to accelerate regeneration. Parameters for electrical stimulation vary greatly. Both AC and DC currents with a range of voltages have been observed to enhance neural tissue regeneration. Direct current electrical stimulation is known to enhance and direct neurite outgrowth (McCaig and Rajnicek 1991). Even brief periods of stimulation caused a sustained increase in neurite growth rate (Wood and Willitz 2006). Electrical fields as low as 10 mV/mm have been shown to guide neurite outgrowth (Rajnicek et al. 1998). The direction of neurite outgrowth was dependent on cell type and the surface on which the cells were cultured. Short-period, low-frequency electrical stimulation studies indicated that 100 ms, 3V pulses delivered at a rate of 20 Hz for periods as brief as 1 h accelerated axonal regeneration and the restoration of motor function (Al-Majed et al. 2000). An in vivo model using dogs with injured spinal cords showed that an oscillating electrical field of 500-600 mV/mm significantly accelerated the return of sensory and motor function at time points of 6 weeks and 6 months (Borgens et al. 1999). While the mechanism by which electrical stimulation enhances neural cell activity are not entirely understood, studies have shown that electrical current passed through substrates (such as electrically conducting polymer polypyrrole (PPy)) can promote fibronectin protein adsorption to enhance neural cell activity in vitro (Kotwal and Schmidt 2001). Upregulation of genes associated the neural tissue growth may help explain this phenomenon. In recent studies, an increase in cAMP was induced in DRG neurons by a brief period of electrical stimulation in a rat model (Udina et al. 2008). Elevated levels of cAMP were evident after the rat was sacrificed and the DRG neurons were plated in vitro. Cells with elevated levels of cAMP produced axons of significantly greater length than control groups. This study demonstrated the sustained effect that a brief period of electrical stimulation has on the neural cell behavior and axonal outgrowth.

Diabetes 2

Diabetes 2

Diabetes is a disease that affects the way your body uses food. Normally, your body converts sugars, starches and other foods into a form of sugar called glucose. Your body uses glucose for fuel. The cells receive the glucose through the bloodstream. They then use insulin a hormone made by the pancreas to absorb the glucose, convert it into energy, and either use it or store it for later use. Learn more...

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