title: Asphyxia induced by umbilical cord occlusion alters glutamatergic and GABAergic synaptic transmission in neurons of the superior colliculus in fetal rats.
abstract: Using optical recordings, we studied the effects of asphyxia on intracellular Cl(-) and Ca(2+) concentrations ([Cl(-)]i; [Ca(2+)]i) in the superior colliculus of fetal rats, which were connected via the umbilical cord to the dam. Acute asphyxia was induced by umbilical cord occlusion. The number of fetal superior colliculus neurons showing GABA-mediated increases in [Cl(-)]i (leading to hyperpolarization) following local synaptic electrical stimulation had decreased by 3 h post-asphyxiation, while the number showing GABA-mediated decreases in [Cl(-)]i (leading to depolarization) increased. [Ca(2+)]i rise, which occurred after acute asphyxiation, was antagonized by both non-NMDA and NMDA receptor antagonists. The increase in [Ca(2+)]i following focal superior colliculus stimulation was markedly attenuated at 3 h post-asphyxiation. These findings suggest that asphyxia induced by umbilical occlusion induces changes in glutamatergic and GABAergic synaptic transmission in the fetal brain.
authors.affiliation: Department of Neuroscience, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube, Yamaguchi 755-8505, Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Sakata
authors.forename: Hisashi
authors.initials: H
authors.lastname: Endoh
authors.forename: Takeshi
authors.initials: T
authors.lastname: Matsushige
authors.forename: Satoko
authors.initials: S
authors.lastname: Furuya
authors.forename: Shoji
authors.initials: S
authors.lastname: Nakamura
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D005311:Fetal Hypoxia / Q000473:pathology / Q000503:physiopathology*; D059330:GABAergic Neurons / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013477:Superior Colliculi / Q000473:pathology / Q000503:physiopathology*; D009435:Synaptic Transmission
chemical_list: D018698:Glutamic Acid