Blockade of N-methyl-D-aspartate receptors prevents cyanide-induced neuronal injury in primary hippocampal cultures.
Cyanide-induced alterations of cytosolic calcium levels and cytotoxicity were examined in primary cultures of rat hippocampus. Cytosolic free Ca2+ ([Ca2+]i) levels were measured in hippocampal neurons using the fluorescent probe, fura 2. A concentration-dependent rise in [Ca2+]i occurred rapidly following exposure of cells to 0.5-10 mM NaCN. In normal medium (1.3 mM Ca2+), 2 mM NaCN produced an increase in [Ca2+]i (172 +/- 27% of control), 45 sec following exposure. Ca2+ elevation produced by NaCN was blocked by removal of Ca2+ from the external medium or by pretreatment with the N-methyl-D-aspartate (NMDA) receptor antagonist, 2-amino-5-phosphonovalerate (APV). The cytotoxicity of cyanide, assessed by measuring the efflux of lactate dehydrogenase, was blocked by APV. These results indicate that in hippocampal neurons, cytosolic Ca2+ accumulation induced by cyanide originates from the extracellular compartment and the NMDA receptor ionophore is a significant route for Ca2+ entry. It is proposed that excitotoxic mechanisms may contribute to altered neuronal homeostasis and injury associated with cyanide.
Department of Pharmacology and Toxicology, School of Pharmacy and Pharmacal Sciences, Purdue University, West Lafayette, Indiana 47907.
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Patel
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Yim
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Isom
D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002413:Cations, Divalent; D002470:Cell Survival / Q000187:drug effects; D046508:Culture Techniques; D016257:Fura-2; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects*; D006863:Hydrogen-Ion Concentration; D009474:Neurons / Q000187:drug effects*; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012966:Sodium Cyanide / Q000037:antagonists & inhibitors / Q000633:toxicity*
D002413:Cations, Divalent; D016194:Receptors, N-Methyl-D-Aspartate; D011189:Potassium Chloride; D015763:2-Amino-5-phosphonovalerate; D012966:Sodium Cyanide; D002118:Calcium; D016257:Fura-2