Summary
Epileptic foci were established by application of Na-penicillin on the exposed parietal cortex of rats (n=66) anesthetized with pentobarbital. Spikes appearing after a brief (>30s) spontaneous interruption of the interjetal discharge were sometimes followed by a spike-triggered spreading depression (STSD) wave, which blocked the activity of the focus for several min. The first recovering spike induced another STSD and repetitive STSD generation continued for up to 20 cycles, with a median cycle duration of 6 min. STSDs appeared more regularly after postictal depression induced by electrical stimulation of the focus or of the symmetrical brain area, and could also be elicited by SD waves evoked by microinjection of 5% KCl into extrafocal cortical regions. An ongoing STSD cycle was interrupted when another penicillin focus in the contralateral hemisphere started to trigger the focal discharge during relative SD refractoriness. STSD waves were observed in 42% of the animals. Attempts to elicit STSD were successful in 70% when the interictal discharge rate was low (<10/min) but mostly failed with higher discharge rates (>30/min). It is suggested that STSD is generated when an isolated epileptic spike appears at the level of decreased potassium clearance and. that repetitive STSDs are produced by synaptically and metabolically mediated interaction between focal discharge and spreading depression.
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References
Aquino-Cias J, Bureš J (1966) The effect of thalamic spreading depression on the epileptic discharge in rats. In: Servit Z (ed) Comparative and cellular pathophysiology of epilepsy. Excerpta Medica Int. Congr. Ser. No 124, Excerpta Medica, Amsterdam, pp 258–269
Bureš J, Burešová O, Fifková E (1961) The effect of cortical and hippocampal spreading depression on activity of bulbopontine reticular units in the rat. Arch Ital Biol 99: 23–32
Bureš J, Burešová O, Křivánek J (1974) The Mechanism and Applications of Leão's Spreading Depression of Electroence-phalographic Activity. Academia, Prague
Bureš J, von Schwarzenfeld I, Brožek G (1975) Blockade of cortical spreading depression by picrotoxin foci of paroxysmal activity. Epilepsia 16: 111–118
Heinemann U, Gutnick MJ (1979) Relation between extracellular potassium concentration and neuronal activities in cat thalamus (VPL) during projection of cortical epileptiform discharge. EEG Clin Neurophysiol 47: 355–357
Heinemann, U, Lux HD (1975) Undershoots following stimulus induced rises of extracellular potassium concentration in cerebral cortex of cat. Brain Res 93: 63–76
Heinemann U, Lux HD (1977) Ceiling of stimulus-induced rises of extracellular potassium concentration in the cerebral cortex of cat. Brain Res 120: 231–249
Heinemann U, Lux HD, Gutnick MJ (1977) Extracellular free calcium and potassium during paroxysmal activity in the cerebral cortex of the cat. Exp Brain Res 17: 237–243
Koroleva VI, Bureš J (1980) Blockade of cortical spreading depression in electrically and chemically stimulated areas of cerebral cortex in rats. EEG Clin Neurophysiol 48: 1–15
Koroleva VI, Bureš J (1979) Circulation of cortical spreading depression around electrically stimulated areas and epileptic foci on the neocortex of rats. Brain Res 173: 209–215
Koroleva VI, Bureš J (1982) Stimulation induced recurrent epileptiform discharges block cortical and subcortical spreading depression in rats. Physiol Bohemoslov 31: 385–400
Leão AAP (1944) Spreading depression of activity in the cerebral cortex. J Neurophysiol 7: 359–390
Lux HD (1974) Kinetics of extracellular potassium: relation to epileptogenesis. Epilepsia 15: 375–393
Moody W, Futamachi FJ, Prince DA (1977) Extracellular potassium activity during epileptogenesis. Exp Neurol 42: 248–263
Nicholson C (1980) Dynamics of the Brain Cell Microenvironment. Neurosci Res Program Bull 18: 177–322
Okujava VM (1980) Role of inhibitory processes in epileptic activity. In: Okujava VM (ed). Neurophysiological Mechanisms of Epilepsy [in Russian]. Metsniereba, Tbilisi, pp 51–59
Prince DA, Lux HD, Neher E (1973) Measurement of extracellular potassium activity in cat cortex. Brain Res 50: 481–495
Reddy MM, Bureš J (1980) Cortical [K+]e and the stimulation induced blockade of spreading depression in the rat cerebral cortex. Neurosci Lett 17: 243–247
Sloan N, Jasper H (1950) The identity of spreading depression and “supression”. EEG Clin Neurophysiol 2: 59–78
Somjen GG (1979) Extracellular potassium in the mammalian central nervous system. Ann Rev Physiol 41: 159–177
Ueda M, Bureš J (1977) Differential effects of cortical spreading depression on epileptic foci induced by various convulsants. EEG Clin Neurophysiol 43: 666–674
Van Harreveld A, Stamm JS (1953) Spreading cortical convulsions and depressions. J Neurophysiol 16: 352–366
Von Harreveld A, Stamm JS (1955) Cortical responses to Metrazol and sensory stimulation in the rabbit. EEG Clin Neurophysiol 7: 363–370
Vyskočil F, Křiž N, Bureš J (1972) Potassium-selective microelektrodes used for measuring the extracellular brain potassium during spreading depression and anoxic depolarization in rats. Brain Res 39: 255–259
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Visiting scientist from the Institute of Higher Nervous Activity and Neurophysiology, Academy of Sciences of the USSR, Moscow, USSR
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Koroleva, V.I., Bureš, J. Cortical penicillin focus as a generator of repetitive spike-triggered waves of spreading depression in rats. Exp Brain Res 51, 291–297 (1983). https://doi.org/10.1007/BF00237205
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DOI: https://doi.org/10.1007/BF00237205