title: Astrocyte/neuron ratio and its importance on glutamate toxicity: an in vitro voltammetric study.
abstract: The purpose of this study was to clarify the relationship between neuron cells and astrocyte cells in regulating glutamate toxicity on the 10th and 20th day in vitro. A mixed primary culture system from newborn rats that contain cerebral cortex neurons cells was employed to investigate the glutamate toxicity. All cultures were incubated with various glutamate concentrations, then viability tests and histological analyses were performed. The activities of glutamate transporters were determined by using in vitro voltammetry technique. Viable cell number was decreased significantly on the 10th day at 10(-7) M and at 10(-6) M glutamate applications, however, viable cell number was not decreased at 20th day. Astrocyte number was increased nearly six times on the 20th day as compared to the 10th day. The peak point of glutamate reuptake capacity was about 2 × 10(-4) M on the 10th day and 10(-3) M on the 20th day. According to our results, we suggested that astrocyte age was important to maintain neuronal survival against glutamate toxicity. Thus, we revealed activation or a trigger point of glutamate transporters on astrocytes due to time since more glutamate was taken up by astrocytes when glutamate transporters on the astrocyte were triggered with high exogenous glutamate concentrations. In conclusion, the present investigation is the first voltammetric study on the reuptake parameters of glutamate in vitro.
authors.affiliation: Department of Medical Pharmacology, Faculty of Medicine, Atatürk University, Erzurum, Turkey. ahmeth@atauni.edu.tr.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Hacimuftuoglu
authors.affiliation: Department of Medical Genetics, Faculty of Medicine, Ataturk University, Erzurum, Turkey.
authors.forename: Abdulgani
authors.initials: A
authors.lastname: Tatar
authors.affiliation: Department of Medical Pharmacology, Faculty of Medicine, Kafkas University, Kars, Turkey.
authors.forename: Damla
authors.initials: D
authors.lastname: Cetin
authors.affiliation: Department of Medical Pharmacology, Faculty of Medicine, Atatürk University, Erzurum, Turkey.
authors.forename: Numan
authors.initials: N
authors.lastname: Taspinar
authors.affiliation: Department of Medical Pharmacology, Faculty of Medicine, Atatürk University, Erzurum, Turkey.
authors.forename: Fatih
authors.initials: F
authors.lastname: Saruhan
authors.affiliation: Department of Medical Pharmacology, Faculty of Medicine, Atatürk University, Erzurum, Turkey.
authors.forename: Ufuk
authors.initials: U
authors.lastname: Okkay
authors.affiliation: Department of Molecular Biology and Genetics, Faculty of Sciences, Erzurum Technical University, Erzurum, Turkey.|Department of Pharmaceutical Sciences, University of "G. D'Annunzio", Chieti, Italy.
authors.forename: Hasan
authors.initials: H
authors.lastname: Turkez
authors.affiliation: Department of Histology, Faculty of Medicine, Ataturk University, Erzurum, Turkey.
authors.forename: Deniz
authors.initials: D
authors.lastname: Unal
authors.affiliation: Department of Physiology and Cell Biology, Medical College, The Ohio State University, Columbus, OH, USA.
authors.forename: Robert Louis
authors.initials: RL
authors.lastname: Stephens
authors.affiliation: Department of Medical Pharmacology, Faculty of Medicine, Erzincan University, Erzincan, Turkey.
authors.forename: Halis
authors.initials: H
authors.lastname: Suleyman
keywords: Astrocyte; Glutamate-uptake; In vitro voltammetry; Neuron; Neurotoxicity