title: Guanosine enhances glutamate uptake in brain cortical slices at normal and excitotoxic conditions.
abstract: 1. The effect of guanosine on L-[2,3-3H]glutamate uptake was investigated in brain cortical slices under normal or oxygen-glucose deprivation (OGD) conditions. 2. In slices exposed to physiological conditions, guanosine (1-100 microM) stimulated glutamate uptake (up to 100%) in a concentration-dependent manner when a high (100 microM) but not a low (1 microM) concentration of glutamate was used. 3. In slices submitted to OGD, guanosine 1 and 100 microM also increased 100 microM glutamate uptake (38 and 70%, respectively). 4. The increasing of glutamate and taurine released to the incubation medium in cortical slices submitted to OGD were significantly attenuated by the presence of guanosine in the incubation medium. 5. Guanosine prevented the increase in propidium iodide incorporation into cortical slices induced by OGD, indicating a protective role against ischemic injury. 6. These results support the hypothesis of a protective role for guanosine during brain ischemia, possibly by activating glutamate uptake into neural cells.
authors.affiliation: Departamento de Bioquímica, ICBS, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil. frizzo@vortex.ufrgs.br
authors.forename: Marcos Emílo dos Santos
authors.initials: ME
authors.lastname: Frizzo
authors.forename: Diogo Rizzato
authors.initials: DR
authors.lastname: Lara
authors.forename: Alexandre de Souza
authors.initials: Ade S
authors.lastname: Prokopiuk
authors.forename: Carmen Regla
authors.initials: CR
authors.lastname: Vargas
authors.forename: Christianne Gazzana
authors.initials: CG
authors.lastname: Salbego
authors.forename: Moacir
authors.initials: M
authors.lastname: Wajner
authors.forename: Diogo Onofre
authors.initials: DO
authors.lastname: Souza
mesh_terms: D000818:Animals; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D002540:Cerebral Cortex / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects / Q000502:physiology; D018698:Glutamic Acid / Q000378:metabolism* / Q000494:pharmacology; D006151:Guanosine / Q000378:metabolism / Q000494:pharmacology*; D020925:Hypoxia-Ischemia, Brain / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D018696:Neuroprotective Agents / Q000378:metabolism / Q000494:pharmacology*; D009498:Neurotoxins / Q000378:metabolism / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013569:Synapses / Q000187:drug effects* / Q000378:metabolism; D013654:Taurine / Q000378:metabolism
chemical_list: D018696:Neuroprotective Agents; D009498:Neurotoxins; D006151:Guanosine; D013654:Taurine; D018698:Glutamic Acid