title: Adaptive changes of extracellular amino acid concentrations in mouse dorsal striatum by 4-AP-induced cortical seizures.
abstract: The striatum is a major target of cerebral cortical output. The cortico-striatal projection has been well described, however, the neurochemical changes that occur in the striatum after prolonged cortical hyperactivation remain to be investigated. In this study, extracellular levels of glutamate, GABA, and alanine levels were measured in the dorsal striatum using microdialysis in anesthetized mice at resting condition and during 4-aminopyridine (4-AP)-induced cortical seizures. After topical application of 4-AP on the primary motor cortex that induced cortical seizures, the extracellular level of striatal GABA increased by 40% in 60 min. By contrast, the extracellular level of striatal glutamate decreased by 20%. Moreover, the surface amounts of striatal glutamate/aspartate transporter (GLAST) and glutamate transporter 1 (GLT-1), the major astrocytic high-affinity glutamate transporters, tended to increase by cortical seizures in 60 min, suggesting a recruitment of the glutamate transporters from internal stores. 4-AP also resulted in a steady increase of alanine levels which are thought to reflect glutamate and pyruvate metabolism in neurons and astrocytes. These observations possibly delineate adaptive changes of striatal metabolism by severe cortical seizures.
authors.affiliation: RIKEN Brain Science Institute, Wako, Saitama, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Nagai
authors.affiliation: RIKEN Brain Science Institute, Wako, Saitama, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Takata
authors.affiliation: RIKEN Brain Science Institute, Wako, Saitama, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Shinohara
authors.affiliation: RIKEN Brain Science Institute, Wako, Saitama, Japan; Saitama University Brain Science Institute, Saitama, Saitama, Japan. Electronic address: hirase@brain.riken.jp.
authors.forename: H
authors.initials: H
authors.lastname: Hirase
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects / Q000502:physiology; D000596:Amino Acids / Q000378:metabolism*; D000675:Ampyrone / Q000633:toxicity; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000633:toxicity; D002851:Chromatography, High Pressure Liquid; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D004195:Disease Models, Animal; D027341:Excitatory Amino Acid Transporter 1 / Q000378:metabolism; D027342:Excitatory Amino Acid Transporter 2 / Q000378:metabolism; D045604:Extracellular Fluid / Q000187:drug effects / Q000378:metabolism*; D007839:Functional Laterality; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D017551:Microdialysis; D009044:Motor Cortex / Q000187:drug effects / Q000378:metabolism*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D012640:Seizures / Q000209:etiology* / Q000473:pathology*
chemical_list: D000596:Amino Acids; D000894:Anti-Inflammatory Agents, Non-Steroidal; D027341:Excitatory Amino Acid Transporter 1; D027342:Excitatory Amino Acid Transporter 2; D016760:Proto-Oncogene Proteins c-fos; C493392:Slc1a3 protein, rat; D000675:Ampyrone
keywords: GLAST; GLT-1; HPLC; basal ganglia; cortical seizures