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.
Patel
M N
MN
Department of Pharmacology and Toxicology, School of Pharmacy and Pharmacal Sciences, Purdue University, West Lafayette, Indiana 47907.
Yim
G K
GK
Isom
G E
GE
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