These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: [Spreading depression--cortical reactions: disorders of the extracellular microenvironment].
    Author: Lehmenkühler A.
    Journal: EEG EMG Z Elektroenzephalogr Elektromyogr Verwandte Geb; 1990 Mar; 21(1):1-6. PubMed ID: 2110883.
    Abstract:
    Changes of brain cell microenvironment in the cerebral cortex of the rat were studied during spreading depression (SD) elicited by KCl application or local cooling. The question was whether the behavior of extracellular ion concentrations, especially of K+, could give some information about the triggering mechanisms of SD at the site where the phenomenon originates in the tissue. SDs elicited by KCl and recorded far from their original sites were associated with disturbances of extracellular ion concentrations and of tissue pO2 and pCO2 showing characteristic time sequences. Under these conditions none of the parameters studied changed before SD development. When an SD was elicited by local cooling extracellular K+ concentration ([K+]0) increased steeply in the mostly cooled cortical layers prior to SD initiation and formed a plateau of about 10 mmol/l resembling the ceiling level for K+ associated with ictal seizure activity. The front of the SD wave moved down slowly to the white matter. Thereby the rectangular rise in [K+]0 prior to SD progressively flattened and finally disappeared. The results suggest that SD evoked by local cooling originates from a primary increase of [K+]0 to the K+ ceiling level and by a secondary breakdown of the mechanisms being responsible for this type of K(+)-regulation. The mechanisms mentioned may be responsible for all kinds of SD-triggering.
    [Abstract] [Full Text] [Related] [New Search]