Epileptiform synchronization in the cingulate cortex

Epilepsia. 2009 Mar;50(3):521-36. doi: 10.1111/j.1528-1167.2008.01779.x. Epub 2008 Oct 30.


Purpose: The anterior cingulate cortex (ACC)--which plays a role in pain, emotions and behavior--can generate epileptic seizures. To date, little is known on the neuronal mechanisms leading to epileptiform synchronization in this structure. Therefore, we investigated the role of excitatory and inhibitory synaptic transmission in epileptiform activity in this cortical area. In addition, since the ACC presents with a high density of opioid receptors, we studied the effect of opioid agonism on epileptiform synchronization in this brain region.

Methods: We used field and intracellular recordings in conjunction with pharmacological manipulations to characterize the epileptiform activity generated by the rat ACC in a brain slice preparation.

Results: Bath-application of the convulsant 4-aminopyridine (4AP, 50 microM) induced both brief and prolonged periods of epileptiform synchronization resembling interictal- and ictal-like discharges, respectively. Interictal events could occur more frequently before the onset of ictal activity that was contributed by N-methyl-D-aspartate (NMDA) receptors. Mu-opioid receptor activation abolished 4AP-induced ictal events and markedly reduced the occurrence of the pharmacologically isolated GABAergic synchronous potentials. Ictal discharges were replaced by interictal events during GABAergic antagonism; this GABA-independent activity was influenced by subsequent mu-opioid agonist application.

Conclusions: Our results indicate that both glutamatergic and GABAergic signaling contribute to epileptiform synchronization leading to the generation of electrographic ictal events in the ACC. In addition, mu-opioid receptors appear to modulate both excitatory and inhibitory mechanisms, thus influencing epileptiform synchronization in the ACC.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 4-Aminopyridine / pharmacology
  • 6-Cyano-7-nitroquinoxaline-2,3-dione / pharmacology
  • Animals
  • Anticonvulsants / pharmacology
  • Cortical Synchronization*
  • Electroencephalography* / drug effects
  • Enkephalin, Ala(2)-MePhe(4)-Gly(5)- / pharmacology
  • Epilepsies, Partial / chemically induced
  • Epilepsies, Partial / physiopathology*
  • Evoked Potentials / drug effects
  • Evoked Potentials / physiology
  • GABA Antagonists / pharmacology
  • Gyrus Cinguli / drug effects
  • Gyrus Cinguli / physiopathology*
  • In Vitro Techniques
  • Male
  • Membrane Potentials / drug effects
  • Membrane Potentials / physiology
  • Neural Inhibition / drug effects
  • Neural Inhibition / physiology
  • Neurons / drug effects
  • Neurons / physiology
  • Piperazines / pharmacology
  • Potassium Channel Blockers / pharmacology
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, AMPA / drug effects
  • Receptors, AMPA / physiology
  • Receptors, GABA-A / drug effects
  • Receptors, GABA-A / physiology
  • Receptors, GABA-B / drug effects
  • Receptors, GABA-B / physiology
  • Receptors, Glutamate / drug effects
  • Receptors, Glutamate / physiology
  • Receptors, Kainic Acid / drug effects
  • Receptors, Kainic Acid / physiology
  • Receptors, N-Methyl-D-Aspartate / drug effects
  • Receptors, N-Methyl-D-Aspartate / physiology
  • Receptors, Opioid / drug effects
  • Receptors, Opioid / physiology
  • Receptors, Opioid, mu / drug effects
  • Receptors, Opioid, mu / physiology
  • Synaptic Transmission / drug effects
  • Synaptic Transmission / physiology


  • Anticonvulsants
  • GABA Antagonists
  • Piperazines
  • Potassium Channel Blockers
  • Receptors, AMPA
  • Receptors, GABA-A
  • Receptors, GABA-B
  • Receptors, Glutamate
  • Receptors, Kainic Acid
  • Receptors, N-Methyl-D-Aspartate
  • Receptors, Opioid
  • Receptors, Opioid, mu
  • Enkephalin, Ala(2)-MePhe(4)-Gly(5)-
  • 6-Cyano-7-nitroquinoxaline-2,3-dione
  • 3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid
  • 4-Aminopyridine