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Spatial Buffering of K+ in Relation to Spreading Depression Models

Spatial Buffering of K+ in Relation to Spreading Depression Models. Tony Gardner-Medwin Physiology (NPP), University College London. G-M, COLES and TSACOPOULOS. Brain Research, 209 (1981) 452-457. [K + ] i (mM). [K + ] i. [K + ] o. G-M, COLES and TSACOPOULOS.

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Spatial Buffering of K+ in Relation to Spreading Depression Models

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  1. Spatial Buffering of K+ in Relation to Spreading Depression Models Tony Gardner-Medwin Physiology (NPP), University College London

  2. G-M, COLES and TSACOPOULOS Brain Research, 209 (1981) 452-457

  3. [K+]i (mM) [K+]i [K+]o G-M, COLES and TSACOPOULOS Brain Research, 209 (1981) 452-457 K+ release from photoreceptors and uptake into glia in bee eye

  4. Flux driven by an electrical gradient Computational analysis Spatial Buffer Mechanism: passive removal & transfer of e-c K+ through (mainly) astrocyte membranes & cytoplasm Transfer Cells: (K+-selective) Flux driven by a chemical gradient Conclusions: SB flux ≈ 5x diffusion flux Space constant ≈ 0.2 mm (rat brain), 0.03 mm (frog brain) G-M (1983) J Physiol 335 393-426

  5. K+ & Spreading Depression Instability theshold for K-induced K release (Hodgkin, Grafstein, Tuckwell & Miura) Rapid K+ rise & recovery in SD G-M (1981) J. exp. Biol., 95, 111-127

  6. SD (like the Migraine Aura) can be aborted by breathing O2+CO2 G-M (1981) J. exp. Biol., 95, 111-127 [Urethane anaesthetised rat]

  7. Current patterns around the SD K+ disturbance G-M (1992) in Spreading Depression, ed. RJ Do Carmo. Exp. Brain Res. Series 23,62-74

  8. Functional MRI : Propagation of SD waves in rat brain MRI : the movie ! [Regions of increased gradient echo (oxygenation sensitive) intensity superimposed on a spin echo image). Frame interval 12.2 s, after 150mM KCl application in a craniotomy chamber. Halothane anaesthetised rat, ] G-M, van Bruggen, Williams & Ahier (1994) J. Cerebral Blood Flow & Metabolism 14,7-11

  9. Slowly changing magnetic Signals from SD in rabbit brain [Urethane anaesthetised rabbit] G-M, Tepley, Barkley, Moran, Nagel-Leiby, Simkins & Welch (1991) Brain Research 540, 153-158.

  10. K+ load (mol/s/L) q Complex Buffer Capacity: combining buffer mechanisms with different dynamics G-M (1986) Ann NY Acad Sci, 481, 287-302

  11. Buffering through net K+ uptake into cells Buffering through diffusion in EC space and Spatial Buffering Buffering Capacities relevant to preventing propagation of Spreading Depression G-M (1986) Ann NY Acad Sci, 481, 287-302

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