Action of 4-aminopyridine on extracellular amino acids in hippocampus and entorhinal cortex: a dual microdialysis and electroencehalographic study in awake rats.
Brain Res Bull
; 53(3): 255-62, 2000 Oct.
Article
em En
| MEDLINE
| ID: mdl-11113578
In order to study the role of amino acids in the hippocampus and the entorhinal cortex during the convulsive process induced by 4-aminopyridine (4-AP), we have used a device allowing the simultaneous microdialysis and the recording of their electrical activity of both regions in freely moving rats. We found that infusion of 4-AP into the entorhinal cortex resulted in a large increase in extracellular glutamate and glutamine and small increases in glycine and taurine levels. Likewise, infusion of 4-AP into the hippocampus resulted in a major increase in glutamate, as well as slight increases in taurine and glycine. In both infused regions the peak concentration of extracellular glutamate was observed 15 min after 4-AP administration. No significant changes were found in the non-infused hippocampus or entorhinal cortex of the same rats. Simultaneous electroencephalographic recordings showed intense epileptiform activity starting during 4-AP infusion and lasting for the rest of the experiment (1 h) in both the entorhinal cortex and the hippocampus. The discharges were characterized by poly-spikes and spike-wave complexes that propagated almost immediately to the other region studied. These findings suggest that increased glutamatergic synaptic function in the circuit that connects both regions is involved in the epileptic seizures induced by 4-AP.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
4-Aminopiridina
/
Córtex Entorrinal
/
Aminoácidos
/
Hipocampo
Limite:
Animals
Idioma:
En
Revista:
Brain Res Bull
Ano de publicação:
2000
Tipo de documento:
Article
País de afiliação:
México
País de publicação:
Estados Unidos