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

4. 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 Computational analysis Flux driven by an electrical gradient G-M (1983) J Physiol 335 393-426 Conclusions: SB flux ≈ 5x diffusion flux Space constant ≈ 0.2 mm (rat brain), 0.03 mm (frog brain)

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

6. G-M (1981) J. exp. Biol., 95, 111-127 SD (like the Migraine Aura) can be aborted by breathing O 2 +CO 2 [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. G-M, van Bruggen, Williams & Ahier (1994) J. Cerebral Blood Flow & Metabolism 14,7-11 Functional MRI : Propagation of SD waves in rat brain [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, ] MRI : the movie !

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

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

11. G-M (1986) Ann NY Acad Sci, 481, 287-302 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