title: Effect of two different routes of administration of R-PIA on glutamate release during ischemia.
abstract: Considering that adenosine decreases glutamate release from brain slices by stimulating presynaptic A1 receptors, we have attempted to modulate glutamate release in vivo during global ischemia with an agonist (R-phenylisopropyladenosine, R-PIA) of A1 receptors. Extracellular hippocampal glutamate was sampled by microdialysis and measured by HPLC. Conscious rats were submitted to transient global ischemia for 20 min. Ischemia induced a significant increase (10 fold) in extracellular glutamate. R-PIA (20 micrograms/kg) administered i.p. 30 min before ischemia significantly reduced (-64%) glutamate release. Conversely, R-PIA (100 microM) continuously infused through the hippocampal dialysis probe did not significantly modify glutamate efflux. The efficiency of infused R-PIA was evidenced by the decrease (-47%) of glutamate release induced by veratridine depolarization. These results indicate that the depressive action of R-PIA during ischemia results from various effects which are not restricted to a local action on the hippocampus.
authors: Laboratoire de Recherches Cérébrovasculaires, URA 641 CNRS, Université Paris VII, France.
authors: A
authors: A
authors: Héron
authors: F
authors: F
authors: Lasbennes
authors: J
authors: J
authors: Seylaz
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002545:Brain Ischemia / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003979:Diazonium Compounds / Q000378:metabolism; D004569:Electroencephalography; D005971:Glutamates / Q000378:metabolism*; D007274:Injections, Intraperitoneal; D008297:Male; D010660:Phenylisopropyladenosine / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D013425:Sulfanilic Acids / Q000378:metabolism; D014701:Veratridine / Q000494:pharmacology
chemical_list: D003979:Diazonium Compounds; D005971:Glutamates; D013425:Sulfanilic Acids; D010660:Phenylisopropyladenosine; D014701:Veratridine; C000469:diazobenzenesulfonic acid