Experimental Brain Research

, Volume 51, Issue 2, pp 291–297

Cortical penicillin focus as a generator of repetitive spike-triggered waves of spreading depression in rats

  • V. I. Koroleva
  • J. Bureš

DOI: 10.1007/BF00237205

Cite this article as:
Koroleva, V.I. & Bureš, J. Exp Brain Res (1983) 51: 291. doi:10.1007/BF00237205


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.

Key words

Spreading depressionPenicillin focusPostictal suppressionPotassium clearanceElectrical stimulation

Copyright information

© Springer-Verlag 1983

Authors and Affiliations

  • V. I. Koroleva
    • 1
  • J. Bureš
    • 1
  1. 1.Institute of PhysiologyCzechoslovak Academy of SciencesPragueCzechoslovakia
  2. 2.Institute of PhysiologyCzechoslovak Academy of SciencesPrague 4Czechoslovakia