Effects of anticonvulsants on spontaneous epileptiform activity which develops in the absence of chemical synaptic transmission in hippocampal slices

U. Heinemann, S. Franceschetti, B. Hamon, A. Konnerth, Y. Yaari

Research output: Contribution to journalArticlepeer-review

70 Scopus citations

Abstract

Spontaneous epileptiform activity (SEA) develops in area CA1 of hippocampal slices, when the Ca2+ concentration in the perfusate is lowered to 0.2 mM, at which level evoked chemical synaptic transmission is blocked. We investigated the effects of different anticonvulsants on this autonomous activity, in order to determine whether the antiepileptic effect can be ascribed to an influence on neuronal excitability. Carbamazepine was the most effective to block SEA at concentrations of 1-15 μM. Phenobarbital and phenytoin depressed SEA at concentrations of 25 μM. Valproate was effective at concentrations of 2-5 mM. Midazolam, a water-soluble benzodiazepine agonist and the N-methyl-d-aspartate antagonists, d-α-aminoadipic acid and 2-amino-7-phosphonoheptanoic acid were ineffective in blocking SEA suggesting that they exert their antiepileptic action by interference with synaptic mechanisms.

Original languageEnglish
Pages (from-to)349-352
Number of pages4
JournalBrain Research
Volume325
Issue number1-2
DOIs
StatePublished - 28 Jan 1985
Externally publishedYes

Keywords

  • anticonvulsants
  • antiepileptic drugs
  • carbamazepine
  • hippocampus
  • low Ca concentration
  • midazolam
  • neuronal hyperactivity
  • phenobarbital
  • phenytoin
  • valproate

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