Intracellular free Ca2+ elevations in cultured astroglia induced by neuroligands playing a role in cerebral ischemia.
For better understanding of glial participation in cerebral ischemia, spectrofluorimetric analysis using the calcium indicator Fura-2AM was applied to examine the role of intracellular free Ca2+ ([Ca2+])i elevation induced by different neuroactive substances in cultured rat brain astrocytes. The activation by the general receptor agonist glutamate resulted in a biphasic cell response in [Ca2+]i. We couldn't observe N-methyl-D-aspartate-evoked [Ca2+]i response at all. Quisqualate triggered a complex [Ca2+]i response in astrocytes consisting of mobilization of Ca2+ from the intracellular stores and also Ca2+ influx from the extracellular space. Kainate elicited a markedly different Ca2+ signal an external Ca(2+)-dependent sustained [Ca2+]i rise resulting from the activation of the ionotropic glutamate receptor. According to our results two types of glutamate receptors, the quisqualate-specific metabotropic and kainate-specific ionotropic receptor, are involved in [Ca2+]i elevation in these cultures. We could monitor agonist-specific cell response to noradrenaline, serotonin, vasopressin and ATP as well in these cultured rat astrocytes.
Torday
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Institute of Experimental Surgery, Szent-Györgyi Albert Medical University, Szeged, Hungary.
Fónagy
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Latzkovits
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D000255:Adenosine Triphosphate / Q000494:pharmacology; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D002545:Brain Ischemia / Q000378:metabolism* / Q000503:physiopathology; D002118:Calcium / Q000032:analysis*; D002478:Cells, Cultured; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism*; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D005110:Extracellular Space / Q000378:metabolism; D005456:Fluorescent Dyes; D016257:Fura-2 / Q000031:analogs & derivatives; D018698:Glutamic Acid / Q000494:pharmacology; D007608:Kainic Acid / Q000494:pharmacology; D016202:N-Methylaspartate / Q000494:pharmacology; D018377:Neurotransmitter Agents / Q000494:pharmacology*; D009638:Norepinephrine / Q000494:pharmacology; D016318:Quisqualic Acid / Q000494:pharmacology; D051381:Rats; D017470:Receptors, Glutamate / Q000187:drug effects; D012701:Serotonin / Q000494:pharmacology; D013050:Spectrometry, Fluorescence; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014667:Vasopressins / Q000494:pharmacology
D000316:Adrenergic alpha-Agonists; D018690:Excitatory Amino Acid Agonists; D005456:Fluorescent Dyes; D018377:Neurotransmitter Agents; D017470:Receptors, Glutamate; D014662:Vasoconstrictor Agents; C049925:fura-2-am; D014667:Vasopressins; D012701:Serotonin; D018698:Glutamic Acid; D016202:N-Methylaspartate; D000255:Adenosine Triphosphate; D016318:Quisqualic Acid; D007608:Kainic Acid; D002118:Calcium; D016257:Fura-2; D009638:Norepinephrine