Acta Biologica Hungarica

, Volume 54, Issue 1, pp 63–78 | Cite as

Potassium Channel Blockers Tetraethylammonium and 4-Aminopyridine Fail to Prevent Microglial Activation Induced by Elevated Potassium Concentration

  • Hajnalka Ábrahám
  • A. Losonczy
  • G. Czéh
  • Gy. LázárEmail author
Open Access


The effect of potassium channel blockers tetraethylammonium and 4-aminopyridine was examined on the elevated K+ concentration-induced microglial activation on rat hippocampal slice preparations. Microglial cells were detected by immunohistochemistry with a monoclonal antibody (OX 42) raised against a type 3 complement receptor. During activation the morphology of the microglial cells changes and the staining intensity increases. The degree of microglial activation was determined by measuring the integrated optical density of the cells. Tetraethylammonium and 4-aminopyridine failed to reduce the elevated K+ concentration-induced microglial activation. Both potassium channel blockers, when applied on the hippocampal slices without K+, caused significantly increased microglial activation as compared to the control slices. In order to check whether the functional alteration of the neuronal population induced by 4-aminopyridine caused the activation of the microglial cells, Schaffer collaterals were cut to block spreading of epileptiform hyperactivity of the CA3 pyramidal cells to the CA1 region. No significant differences were found in microglial activation between the CA3 and CA1 regions, indicating that the effect of 4-aminopyridine on microglial cells is independent of the epileptiform activity caused by the drug.


Glial cells epileptiform activity electrophysiology OX-42 



This work was supported by the grants of the Hungarian Science Research Fund (OTKA) T 025759 and A 234.


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© Akadémiai Kiadó, Budapest 2003

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Authors and Affiliations

  • Hajnalka Ábrahám
    • 1
  • A. Losonczy
    • 4
  • G. Czéh
    • 2
  • Gy. Lázár
    • 3
    Email author
  1. 1.Central Electron Microscopic LaboratoryPécsHungary
  2. 2.Department of Pharmacology and PharmacotherapyPécsHungary
  3. 3.Department of Human AnatomyPécs University, Medical FacultyPécsHungary
  4. 4.Institute of Experimental Medicine of the Hungarian Academy of SciencesBudapestHungary

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