Hypoxia suppresses kainate-induced gamma-oscillations in rat hippocampal slices.
Hypoxia or global ischemia causes rapid loss of consciousness and a sudden increase in spontaneous transmitter release suggesting that coordinated synaptic activity is impaired. Gamma oscillations (30-100 Hz) are thought to provide for binding of parallel processed information in the brain, contributing to cognition and formation of short-term memory. We hypothesized that gamma-oscillations are rapidly blocked by hypoxia and that prolonged hypoxia reduces the capability to generate such activity. In ventral hippocampal slices, kainate-induced gamma-oscillations reversibly declined 40 s after onset of 3 min hypoxia. Repetition of such hypoxic periods led to accumulative impairment of gamma-activities. By contrast, 6 min of hypoxia led to a transient anoxic depolarization after which gamma-oscillations remained almost completely blocked.
Fano
Silvia
S
Johannes Mueller-Center for Physiology, Institute for Neurophysiology, Charité-Universitätsmedizin Berlin, Tucholskystrasse 2, 10117 Berlin, Germany.
Behrens
Christoph J
CJ
Heinemann
Uwe
U
D000818:Animals; D003627:Data Interpretation, Statistical; D004569:Electroencephalography / Q000187:drug effects*; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects*; D002534:Hypoxia, Brain / Q000503:physiopathology*; D066298:In Vitro Techniques; D007608:Kainic Acid / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects; D017966:Pyramidal Cells / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar
D018690:Excitatory Amino Acid Agonists; D007608:Kainic Acid