In limbic seizures, neuronal excitation is conveyed from the entorhinal cortex directly to CA1 and subicular regions. This phenomenon is associated with a reduced ability of CA3 to respond to entorhinal cortex inputs. Here, we describe a lesion that destroys the perforant path in CA3 after status epilepticus (SE) induced by pilocarpine injection in 8-week-old rats. Using magnetic resonance imaging, immunohistochemical, and ultrastructural analyses, we determined that this lesion develops after 30 minutes of SE and is characterized by microhemorrhages and ischemia. After a longer period of SE, the lesion invariably involves the upper blade of the dentate gyrus. Adult rats treated with subcutaneous diazepam (20 mg kg(-1) for 3 days) did not develop the dentate gyrus lesion and had less frequent spontaneous recurrent seizures (p < 0.01). Young (3-week-old) rats rarely (20%) developed the CA3 lesion, and their spontaneous seizures were delayed (p < 0.01). To investigate the role of the damaged CA3 in seizure activity, we reinduced SE in adult and young epileptic rats. Using FosB/Delta FosB markers, we found induction of FosB/Delta FosB immunopositivity in CA3 neurons of young but not in adult rats. These experiments indicate that SE can produce a focal lesion in the perforant path that may affect the roles of the hippocampus in epileptic rats.

Proepileptic influence of a focal vascular lesion affecting entorhinal cortex-CA3 connections after status epilepticus / Giuseppe, Biagini; Enrica, Baldelli; Daniela, Longo; Miranda Baccarani, Contri; Uliano, Guerrini; Luigi, Sironi; Paolo, Gelosa; Isabella, Zini; David S., Ragsdale; Avoli, Massimo. - In: JOURNAL OF NEUROPATHOLOGY AND EXPERIMENTAL NEUROLOGY. - ISSN 0022-3069. - STAMPA. - 67:7(2008), pp. 687-701. [10.1097/nen.0b013e318181b8ae]

Proepileptic influence of a focal vascular lesion affecting entorhinal cortex-CA3 connections after status epilepticus

AVOLI, Massimo
2008

Abstract

In limbic seizures, neuronal excitation is conveyed from the entorhinal cortex directly to CA1 and subicular regions. This phenomenon is associated with a reduced ability of CA3 to respond to entorhinal cortex inputs. Here, we describe a lesion that destroys the perforant path in CA3 after status epilepticus (SE) induced by pilocarpine injection in 8-week-old rats. Using magnetic resonance imaging, immunohistochemical, and ultrastructural analyses, we determined that this lesion develops after 30 minutes of SE and is characterized by microhemorrhages and ischemia. After a longer period of SE, the lesion invariably involves the upper blade of the dentate gyrus. Adult rats treated with subcutaneous diazepam (20 mg kg(-1) for 3 days) did not develop the dentate gyrus lesion and had less frequent spontaneous recurrent seizures (p < 0.01). Young (3-week-old) rats rarely (20%) developed the CA3 lesion, and their spontaneous seizures were delayed (p < 0.01). To investigate the role of the damaged CA3 in seizure activity, we reinduced SE in adult and young epileptic rats. Using FosB/Delta FosB markers, we found induction of FosB/Delta FosB immunopositivity in CA3 neurons of young but not in adult rats. These experiments indicate that SE can produce a focal lesion in the perforant path that may affect the roles of the hippocampus in epileptic rats.
2008
hemorrhage; hippocampus; immediate early genes; ischemia; magnetic resonance imaging; pilocarpine; temporal lobe epilepsy
01 Pubblicazione su rivista::01a Articolo in rivista
Proepileptic influence of a focal vascular lesion affecting entorhinal cortex-CA3 connections after status epilepticus / Giuseppe, Biagini; Enrica, Baldelli; Daniela, Longo; Miranda Baccarani, Contri; Uliano, Guerrini; Luigi, Sironi; Paolo, Gelosa; Isabella, Zini; David S., Ragsdale; Avoli, Massimo. - In: JOURNAL OF NEUROPATHOLOGY AND EXPERIMENTAL NEUROLOGY. - ISSN 0022-3069. - STAMPA. - 67:7(2008), pp. 687-701. [10.1097/nen.0b013e318181b8ae]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/77800
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