title: Glutamate and dopamine receptors contribute to the lateral spread of epileptiform discharges in rat neocortical slices.
abstract: OBJECTIVE
  The effects of AMPA-type glutamate receptor as well as dopamine D1 and D2 receptors on the lateral propagation of epileptiform field potentials (EFP) were studied across adjacent areas of rat neocortical tissues.
  
  
  METHODS
  Epileptiform burst discharges were induced by superfusion of Mg(2+)-free artificial cerebrospinal fluid. Simultaneous field potential recordings of EFP were obtained from four microelectrodes placed 2-3 mm apart across coronal slices in the third layer of the neocortex. The effects of AMPA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), dopamine D1 receptor agonist SKF 81297, and dopamine D2 receptor agonist quinpirole on lateral propagation of burst discharges were investigated.
  
  
  RESULTS
  CNQX, applied focally between recording sites, blocked rapid propagation across treated areas and resulted in the emergence of spatially separate, independent pacemakers. Focal application of SKF 81297 between recording sites increased the repetition rate of EFP, but reduced the amplitude as well as the duration of epileptic discharges. However, addition of SKF 81297 to the bath medium abolished EFP. Both local and systemic applications of quinpirole irreversibly enhanced repetition rate of epileptiform burst discharges.
  
  
  CONCLUSIONS
  The results indicate the prerequisite of AMPA synaptic transmission for synchronized lateral propagation of Mg(2+)-free ACSF-induced epileptic activity and the modulatory effects of dopamine D1 and D2 receptors on both EFP initiation and propagation in epileptic tissues.
authors.affiliation: Institut für Physiologie I, Westfalische Wilhelms-Universitat Münster, Münster, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Goda
authors.forename: Stjepana
authors.initials: S
authors.lastname: Kovac
authors.forename: Erwin-Josef
authors.initials: EJ
authors.lastname: Speckmann
authors.forename: Ali
authors.initials: A
authors.lastname: Gorji
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004827:Epilepsy / Q000503:physiopathology*; D008564:Membrane Potentials / Q000502:physiology; D008959:Models, Neurological; D019579:Neocortex / Q000503:physiopathology*; D009434:Neural Pathways / Q000503:physiopathology; D051381:Rats; D011954:Receptors, Dopamine / Q000502:physiology*; D017470:Receptors, Glutamate / Q000502:physiology*
chemical_list: D011954:Receptors, Dopamine; D017470:Receptors, Glutamate