In this study we report that in the presence of normal buffer, epileptiform dischargesoccur spontaneously (duration=2.60±0.49 s) or can be induced by electrical stimuli(duration=2.50±0.62 s) in the entorhinal cortex (EC) of brain slices obtained frompilocarpine-treated rats but not in those from age-matched, nonepileptic control (NEC)animals. These network-driven epileptiform events consist of field oscillatory sequences atfrequencies greater than 200 Hz that most often initiate in the lateral EC and propagateto the medial EC with 4–63 ms delays. The NMDA receptor antagonist CPP depressesthe rate of occurrence (P <0.01) of these spontaneous epileptiform discharges but failsin blocking them. Paradoxically, stimulus-induced epileptiform responses are enhanced induration during CPP application.However, concomitant application ofNMDAand non-NMDAglutamatergic antagonists abolishes spontaneous and stimulus-induced epileptiform events.Intracellular recordings from lateral EC layer V cells indicate a lower frequency of spontaneoushyperpolarizing postsynaptic potentials in pilocarpine-treated tissue than in NEC (P <0.002)both under control conditions and with glutamatergic receptor blockade; the reversal potentialof pharmacologically isolated GABAA receptor-mediated inhibitory postsynaptic potentialshas similar values in the two types of tissue. Finally, immunohistochemical analysis showsthat parvalbumin-positive interneurons are selectively reduced in number in EC deep layers.Collectively, these results indicate that reduced inhibition within the pilocarpine-treated EClayer V may promote network epileptic hyperexcitability.

Network hyperexcitability within the deep layers of pilocarpine-treated entorhinal cortex / P., De Guzman; Y., Inaba; Baldelli, Enrica; M., De Curtis; Biagini, Giuseppe; M., Avoli. - In: THE JOURNAL OF PHYSIOLOGY. - ISSN 0022-3751. - STAMPA. - 586:(2008), pp. 1867-1883.

Network hyperexcitability within the deep layers of pilocarpine-treated entorhinal cortex.

BALDELLI, Enrica;BIAGINI, Giuseppe;
2008

Abstract

In this study we report that in the presence of normal buffer, epileptiform dischargesoccur spontaneously (duration=2.60±0.49 s) or can be induced by electrical stimuli(duration=2.50±0.62 s) in the entorhinal cortex (EC) of brain slices obtained frompilocarpine-treated rats but not in those from age-matched, nonepileptic control (NEC)animals. These network-driven epileptiform events consist of field oscillatory sequences atfrequencies greater than 200 Hz that most often initiate in the lateral EC and propagateto the medial EC with 4–63 ms delays. The NMDA receptor antagonist CPP depressesthe rate of occurrence (P <0.01) of these spontaneous epileptiform discharges but failsin blocking them. Paradoxically, stimulus-induced epileptiform responses are enhanced induration during CPP application.However, concomitant application ofNMDAand non-NMDAglutamatergic antagonists abolishes spontaneous and stimulus-induced epileptiform events.Intracellular recordings from lateral EC layer V cells indicate a lower frequency of spontaneoushyperpolarizing postsynaptic potentials in pilocarpine-treated tissue than in NEC (P <0.002)both under control conditions and with glutamatergic receptor blockade; the reversal potentialof pharmacologically isolated GABAA receptor-mediated inhibitory postsynaptic potentialshas similar values in the two types of tissue. Finally, immunohistochemical analysis showsthat parvalbumin-positive interneurons are selectively reduced in number in EC deep layers.Collectively, these results indicate that reduced inhibition within the pilocarpine-treated EClayer V may promote network epileptic hyperexcitability.
586
1867
1883
Network hyperexcitability within the deep layers of pilocarpine-treated entorhinal cortex / P., De Guzman; Y., Inaba; Baldelli, Enrica; M., De Curtis; Biagini, Giuseppe; M., Avoli. - In: THE JOURNAL OF PHYSIOLOGY. - ISSN 0022-3751. - STAMPA. - 586:(2008), pp. 1867-1883.
P., De Guzman; Y., Inaba; Baldelli, Enrica; M., De Curtis; Biagini, Giuseppe; M., Avoli
File in questo prodotto:
File Dimensione Formato  
JPhys.ECdeeplayers.pdf

accesso aperto

Tipologia: Versione dell'editore (versione pubblicata)
Dimensione 951.62 kB
Formato Adobe PDF
951.62 kB Adobe PDF Visualizza/Apri
Pubblicazioni consigliate

Caricamento pubblicazioni consigliate

Licenza Creative Commons
I metadati presenti in IRIS UNIMORE sono rilasciati con licenza Creative Commons CC0 1.0 Universal, mentre i file delle pubblicazioni sono rilasciati con licenza Attribuzione 4.0 Internazionale (CC BY 4.0), salvo diversa indicazione.
In caso di violazione di copyright, contattare Supporto Iris

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11380/583432
Citazioni
  • ???jsp.display-item.citation.pmc??? 16
  • Scopus 27
  • ???jsp.display-item.citation.isi??? 26
social impact