Homeostasis of extracellular fluid in retinas of invertebrates and vertebrates

Coles, J. A. (1986) Homeostasis of extracellular fluid in retinas of invertebrates and vertebrates. In: Autrum, H., Ottoson, D., Perl, E. R., Schmidt, R. S., Shimazu, H. and Willis, W. D. (eds.) Progress in Sensory Physiology. Springer, pp. 105-138. ISBN 9783642704130 (doi: 10.1007/978-3-642-70411-6_3)

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Publisher's URL: http://dx.doi.org/10.1007/978-3-642-70411-6_3


When a neurone is active, movement of ions and water across its membrane will tend to modify the composition of the fluid in the adjacent extracellular space. Usually, K<sup>+</sup> is the ion of particular interest because the relative changes in its extracellular concentration (K<sub>0</sub> ) can be large, up to more than fourfold, and because these changes will modify the excitability both of the neurone itself and of any of its neighbours that are exposed to a raised K<sub>0</sub> (e.g., Frankenhaeuser and Hodgkin 1956, Baylor and Nicholls 1969). There is direct evidence that this K<sup>+</sup> mediates signal transmission between giant neurones in the cockroach (Yarom and Spira 1982), and the strongly suggestive evidence that it plays a role in nervous integration in many parts of the central nervous system is the major theme of the reviews by Orkand (1980) and Sykova (1983). But in most nervous tissue, the interposition of glial cells between neurones, and the geometry and membrane properties of these glia, have led to the suggestion that one of the roles of the glia is to contribute to the homeostasis of the extracellular fluid, particularly by removing K<sup>+</sup> from those clefts where its concentration is elevated (Orkand et al. 1966, see Connors et al. 1982 for a recent example). General principles have been set out by Gardner–Medwin (1980, 1983b) and there are reviews by Kuffler and Nicholls (1966), Somjen (1979, 1981), Walz and Hertz (1983a) and Newman (1985a).

Item Type:Book Sections
Glasgow Author(s) Enlighten ID:Coles, Dr Jonathan
Authors: Coles, J. A.
College/School:College of Medical Veterinary and Life Sciences > Institute of Infection Immunity and Inflammation

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