Ischemic tolerance preserves propagation of membrane depolarization.
The functional integrity of the synaptic connections within the hippocampus in gerbils that had acquired ischemic tolerance was investigated. The propagation of membrane depolarization across the hippocampus in response to electrical stimulation of CA1 was monitored with the use of a high speed optical recording technique. In comparison to control slices, propagation was significantly depressed and depolarization was shortened in slices from gerbils subjected to 5 min of ischemia. Hippocampal slices from gerbils who were preconditioned with prior sublethal ischemia demonstrated only a slight reduction in propagation. The duration of depolarization was longer than that of ischemia group. These findings suggest that ischemia induces a functional disturbance of synaptic transmission and membrane depolarization. Ischemic preconditioning significantly reduced the extent of this functional disturbance.
Taga
K
K
Department of Anesthesiology, Niigata University School of Medicine, Niigata, Japan.
Fujiwara
N
N
Shimoji
K
K
D000818:Animals; D002545:Brain Ischemia / Q000473:pathology / Q000503:physiopathology*; D004558:Electric Stimulation; D001330:Electronic Data Processing / Q000706:statistics & numerical data; D005456:Fluorescent Dyes; D005849:Gerbillinae; D006624:Hippocampus / Q000473:pathology / Q000503:physiopathology*; D019194:Ischemic Preconditioning; D008297:Male; D008564:Membrane Potentials / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D011726:Pyridinium Compounds; D009435:Synaptic Transmission / Q000502:physiology
D005456:Fluorescent Dyes; D011726:Pyridinium Compounds; C054158:RH 414