title: An analytical flow injection system to measure glutamate in microdialysis samples based on an enzymatic reaction and electrochemical detection.
abstract: Glutamate (Glu) is the main excitatory neurotransmitter in the brain for which several methods have been developed to measure this compound in extracellular brain fluids. Most of these techniques are based on coupling microdialysis to HPLC and they have a resolution time of about 10 min. Here, we present a different approach to measure Glu with a resolution of about 1 min per microdialysis sample, enabling a better relationship to be established between EEG activity and biochemical changes. This new setup was used to determine the time delay between the tip of the microdialysis probe and the site of sample collection, and was accurate to within seconds. Indeed, the measurement of Glu concentrations was linear. Administration of 4-aminopyridine was used to provoke seizure convulsions and under these conditions, biochemical changes and EEG activity were evaluated. These experimental data support the key role of Glu in the initiation of a seizure convulsion.
authors.affiliation: Departamento de Biología Celular y Molecular, Centro Universitario de Ciencias Biológicas y Agropecuarias, Universidad de Guadalajara, Km.15.5 Carretera Guadalajara-Nogales S/N, CP 45110, Guadalajara, Jalisco, México. amorales@cucba.udg.mx
authors.forename: Alberto
authors.initials: A
authors.lastname: Morales-Villagrán
authors.forename: Cuauhtemoc
authors.initials: C
authors.lastname: Sandoval-Salazar
authors.forename: Laura
authors.initials: L
authors.lastname: Medina-Ceja
mesh_terms: D015761:4-Aminopyridine / Q000378:metabolism; D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods; D004569:Electroencephalography; D018698:Glutamic Acid / Q000032:analysis*; D006624:Hippocampus / Q000378:metabolism; D008297:Male; D017551:Microdialysis; D026902:Potassium Channel Blockers / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012640:Seizures / Q000139:chemically induced / Q000503:physiopathology; D013997:Time Factors
chemical_list: D026902:Potassium Channel Blockers; D018698:Glutamic Acid; D015761:4-Aminopyridine