Potentiation of intracellular Ca2+ mobilization by hypoxia-induced NO generation in rat brain striatal slices and human astrocytoma U-373 MG cells and its involvement in tissue damage.

Abstract

The relationship between nitric oxide (NO) and intracellular Ca2+ in hypoxic-ischemic brain damage is not known in detail. Here we used rat striatal slices perfused under low-oxygen and Ca2+-free conditions and cultured human astrocytoma cells incubated under similar conditions as models to study the dynamics of intracellular NO and Ca2+ in hypoxia-induced tissue damage. Exposure of rat striatal slices for 70 min to low oxygen tension elicited a delayed and sustained increase in the release of 45Ca2+. This was potentiated by the NO donors sodium nitroprusside (SNP) and spermine-NO and inhibited by N-omega-nitro-L-arginine methyl ester (L-NAME) or by the NO scavenger 2-phenyl-4,4,5,5 tetramethylimidazoline-1-oxyl-3-oxide (PTIO). A membrane-permeant form of heparin in combination with either ruthenium red (RR) or ryanodine (RY) also inhibited 45Ca2+ release. In human astrocytoma U-373 MG cells, hypoxia increased intracellular Ca2+ concentration ([Ca2+]i) by 67.2 +/- 13.1% compared to normoxic controls and this effect was inhibited by L-NAME, PTIO or heparin plus RR. In striatal tissue, hypoxia increased NO production and LDH release and both effects were antagonized by L-NAME. Although heparin plus RR or RY antagonized hypoxia-induced increase in LDH release they failed to counteract increased NO production. These data therefore indicate that NO contributes to hypoxic damage through increased intracellular Ca2+ mobilization from endoplasmic reticulum and suggest that the NO-Ca2+ signalling might be a potential therapeutic target in hypoxia-induced neuronal degeneration.

• Authors: Antonella Meini, Alberto Benocci, Maria Frosini, Gian Pietro Sgaragli, Julian Blanco Garcia, Gian Paolo Pessina, Carlo Aldinucci, Mitri Palmi
• Journal: The European journal of neuroscience (Eur J Neurosci) Vol. 17 Issue 4 Pg. 692-700 (Feb 2003) ISSN: 0953-816X [Print] France
• PMID: 12603259 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Anticoagulants
• Cyclic N-Oxides
• Drug Combinations
• Enzyme Inhibitors
• Free Radical Scavengers
• Imidazoles
• Nitric Oxide Donors
• fura-2-am
• Ryanodine
• Nitroprusside
• 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide
• Nitric Oxide
• Ruthenium
• Heparin
• Hydro-Lyases
• lactate dehydratase
• Calcium
• Fura-2
• NG-Nitroarginine Methyl Ester

Topics

• Animals
• Anticoagulants (pharmacology)
• Astrocytoma
• Calcium (metabolism)
• Cell Line, Tumor
• Corpus Striatum (drug effects, metabolism)
• Cyclic N-Oxides (pharmacology)
• Dose-Response Relationship, Drug
• Drug Combinations
• Drug Interactions
• Enzyme Inhibitors (pharmacology)
• Free Radical Scavengers (pharmacology)
• Fura-2 (analogs & derivatives, metabolism)
• Heparin (pharmacology)
• Humans
• Hydro-Lyases (metabolism)
• Hypoxia (metabolism, physiopathology)
• Imidazoles (pharmacology)
• In Vitro Techniques
• Intracellular Space (metabolism)
• Male
• NG-Nitroarginine Methyl Ester (pharmacology)
• Nitric Oxide (metabolism)
• Nitric Oxide Donors (pharmacology)
• Nitroprusside (pharmacology)
• Perfusion (methods)
• Rats
• Rats, Sprague-Dawley
• Ruthenium (pharmacology)
• Ryanodine (pharmacology)