Chapter

Extracellular Potassium and pH: Homeostasis and Signaling

Jonathan A. Coles and Joachim W. Deitmer

in Neuroglia

Published on behalf of Oxford University Press

Published in print October 2004 | ISBN: 9780195152227
Published online September 2013 | e-ISBN: 9780199865024 | DOI: http://dx.doi.org/10.1093/acprof:oso/9780195152227.003.0026
                      Extracellular Potassium and pH: Homeostasis and Signaling

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This chapter focuses on signaling and homeostasis. Electrical signaling in nervous systems involves considerable fluxes of ions across the neuronal membranes to carry electrical charge in and out. These ion fluxes tend to change the ion concentrations inside and outside cells, and these concentration changes, if sufficiently large, would change the functioning of cells and hence of the tissue as a whole. Changes in ion concentrations are usually opposed by homeostatic processes and, in general, are not large enough to have radical effects on function. However, modest changes in ion concentrations during physiological activity are often observed, and some of these can be regarded as signals passing through the extracellular spaces (ECS). Ions participating in major fluxes across cell membranes include those responsible for electrical signaling (mainly Na+, K+, and Cl-), and also HCO3-, H+, and NH4+, which are linked to metabolism.

Keywords: glial cells; astrocytes; sodium; extracellular potassium; ammonium

Chapter.  9525 words.  Illustrated.

Subjects: Neuroscience

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