Calcium transients in the model of rapidly induced anoxic tolerance in rat cortical slices: involvement of NMDA receptors.
In this study, we investigated the effects of NMDA receptor antagonists on calcium transients induced by a single 2-min preconditioning anoxia (PA) in rat olfactory cortical slices, and on the ability of PA to prevent pathological calcium overload induced by subsequent 10-min test anoxia (TA). Relative changes in the intracellular Ca(2+) concentration (Ca(i)) and in the level of Ca(2+) bound to intracellular hydrophobic domains (Ca(b)) were monitored using fura-2 and chlortetracycline, respectively. Our results confirmed that TA induces prominent long-lasting increases in Ca(i) and Ca(b), reflecting cellular calcium overload. It was found that PA produces moderate increases in both Ca(2+) pools and prevents Ca(2+) overload induced by TA carried out 90 min later. Calcium transients and the protective effects of PA were significantly suppressed in slices treated with NMDA receptor antagonists during and 30 min after PA. These results indicate that moderate activation of the NMDA receptors participates in the mechanism of the PA-induced anoxic tolerance of cortical neurons.
Semenov
Dmitry G
DG
Pavlov Institute of Physiology, Russian Academy of Sciences, St Petersburg, Russia.
Samoilov
Mikhail O
MO
Łazarewicz
Jerzy W
JW
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005456:Fluorescent Dyes; D002534:Hypoxia, Brain / Q000378:metabolism* / Q000503:physiopathology; D019194:Ischemic Preconditioning; D008297:Male; D008954:Models, Biological; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology
D018691:Excitatory Amino Acid Antagonists; D005456:Fluorescent Dyes; D016194:Receptors, N-Methyl-D-Aspartate; D002118:Calcium