Physiological Gradients of Voltage as Controls of Neural Morphogenesis
It has long been suspected that endogenous steady ionic currents and natural voltage gradients may play a role in the early development of animals and plants9,10,13,15. For example, the cytoplasmic localizations in germinating fucus eggs may be controlled by a steady transcellular calcium current11,18, and a steady outwardly directed ionic current predicts the exact locus of limb development in both frog and salamander embryos4,5,19.Transcellular currents also play a critical role in cell and tissue reactions to injury and in their subsequent regeneration1,3,14. These experiments also provide insights into the use of imposed voltage gradients as a clinical treatment for nervous system trauma3. More recently, new studies provide direct evidence for a controlling role of endogenous currents and voltages in vertebrate morphogenesis, particularly when we restrict our attention to the early nervous system.
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