Address of Corresponding Author

Neurosignals 2004;13:290-297 (DOI: 10.1159/000081964)

  Key Words

• Kainic acid
• Chronic temporal lobe epilepsy model
• Glutamic acid decarboxylase
• Choline acetyltransferase
• Somatostatin
• Cortical regions
• Neuroprotection
• Neurodegeneration
• Epileptogenesis
• Brain
• Rat

  Abstract

The aim of the study was to investigate neurochemical changes in a kainic acid (KA; 10 mg/kg, s.c.)-induced spontaneous recurrent seizure model of epilepsy, 6 months after the initial KA-induced seizures. The neuronal markers of cholinergic and -aminobutyric acid (GABA)ergic systems, i.e. choline acetyltransferase (ChAT) and glutamic acid decarboxylase (GAD) activities, and a marker for neuropeptide, i.e. level of somatostatin, have been investigated. The brain regions investigated were the hippocampus, amygdala/piriform cortex, caudate nucleus, substantia nigra and the frontal, parietal, temporal and occipital cortices. Six months after KA injection, reduced ChAT activity was observed in the amygdala/piriform cortex (47% of control; p < 0.001), increased ChAT activity in the hippocampus (119% of control; p < 0.01) and normal ChAT activity in the other brain regions. The activity of GAD was significantly increased in all analysed cortical regions (between 146 and 171% of control), in the caudate nucleus (144% of control; p < 0.01) and in the substantia nigra (126% of control; p < 0.01), whereas in the amygdala/piriform cortex, the GAD activity was moderately lowered. The somatostatin level was significantly increased in all cortical regions (between 162 and 221% of control) as well as in the hippocampus (119% of control), but reduced in the amygdala/piriform cortex (45% of control; p < 0.01). Six months after KA injection, the somatostatin:GAD ratio was lowered in the amygdala/piriform cortex (49% of control) and in the caudate nucleus (41% of control), whereas it was normal in the hippocampus and moderately increased in the cortical brain regions. A positive correlation was found between seizure severity and the reduction of both ChAT activities and somatostatin levels in the amygdala/piriform cortex. The results show a specific pattern of changes for cholinergic, GABAergic and somatostatinergic activities in the chronic KA model for epilepsy. The revealed data suggest a functional role for them in the new network that follows spontaneous repetitive seizures.

Copyright © 2004 S. Karger AG, Basel

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  Author Contacts

Halina Baran, PhD
Institute of Pharmacology and Toxicology
Veterinary University Vienna
AT-1210 Vienna (Austria)
Tel. +43 1 25077 4519, Fax +43 1 25077 4590, E-Mail Halina.Baran@vu-wien.ac.at

  Article Information

Received: April 7, 2004
Accepted after revision: August 19, 2004
Number of Print Pages : 8
Number of Figures : 1, Number of Tables : 4, Number of References : 45

  Publication Details

Neurosignals

Vol. 13, No. 6, Year 2004 (Cover Date: November-December 2004)

Journal Editor: N.Y. Ip, Hong Kong
ISSN: 1424-862X (print), 1424-8638 (Online)

For additional information: http://www.karger.com/nsg

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