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2-APV and DGAMS are superior to MK-801 in preventing hypoxia-induced injury to developing neurons in vitro
1University of Minnesota School of Medicine; Minneapolis.
Abstract:
The relative efficacy of competitive and noncompetitive excitatory amino acid antagonists in preventing hypoxic neuronal injury recently was examined in vitro. Immature (26 days post-conception) fetal mouse cerebral cortical cell cultures were exposed 10 days after plating to 5% oxygen for 24 hrs and returned to normoxia. After hypoxic insult, cultures were either not treated or the medium was supplemented with the competitive excitatory amino acid antagonists 2-amino-5-phosphonovalerate (2-APV), gamma-D-glutamylaminomethylsulphonate (DGAMS), or the noncompetitive antagonist methyl-10,11-dihydro-5-H-dibenzocyclohepten-5,10-imine maleate (MK-801). By 48 hrs after restitution of normoxia, untreated hypoxic cultures evidenced severe neuronal deterioration, elevated LDH concentrations in the medium, depressed benzodiazepine receptor binding, and reduced GABA and glutamate uptake. Enhanced glial cell activity was reflected by modestly elevated glutamine synthetase activity. In hypoxic cultures treated with 2-APV (10 microM) or DGAMS (30 microM), neuronal morphology and biochemical profiles were both improved significantly when compared to both untreated hypoxic cultures and also to those treated with MK-801; 2-APV provided greater, although incomplete, protection. MK-801, at the highest nonneurotoxic concentration (25 nM), did not improve neuronal viability when compared to untreated controls. These results suggest that competitive excitatory amino acid antagonists are superior to noncompetitive antagonists in preventing hypoxic neuronal injury to developing neurons in vitro. MK-801, at low concentrations, produced significant neurotoxicity without improving cell survival.
Insights
Competitive excitatory amino acid antagonists, like 2-APV, better protect developing neurons from hypoxic injury than noncompetitive ones. MK-801 showed no benefit and caused neurotoxicity in vitro.
Area of Science:
- Neuroscience
- Neuroprotection
- Developmental Biology
Background:
- Hypoxic neuronal injury is a significant concern in developing brains.
- Excitatory amino acid antagonists are explored for neuroprotective strategies.
- Understanding antagonist efficacy is crucial for therapeutic development.
Purpose of the Study:
- To compare the efficacy of competitive and noncompetitive excitatory amino acid antagonists in preventing in vitro hypoxic neuronal injury.
- To evaluate the neuroprotective potential of 2-amino-5-phosphonovalerate (2-APV), gamma-D-glutamylaminomethylsulphonate (DGAMS), and MK-801.
- To assess the neurotoxicity of MK-801 at specific concentrations.
Main Methods:
- Primary fetal mouse cerebral cortical cell cultures were subjected to 24-hour hypoxia (5% oxygen).
- Cultures were treated with competitive antagonists (2-APV, DGAMS) or a noncompetitive antagonist (MK-801) post-hypoxia.
- Neuronal viability, morphology, LDH levels, receptor binding, and neurotransmitter uptake were assessed.
Main Results:
- Untreated hypoxic cultures showed severe neuronal damage and biochemical alterations.
- Competitive antagonists 2-APV and DGAMS significantly improved neuronal morphology and biochemical profiles compared to untreated controls.
- MK-801 did not improve neuronal viability and exhibited neurotoxicity at tested concentrations.
Conclusions:
- Competitive excitatory amino acid antagonists are more effective than noncompetitive antagonists in protecting developing neurons from hypoxic injury in vitro.
- 2-APV demonstrated superior neuroprotection compared to DGAMS, though protection was incomplete.
- MK-801 is not suitable for preventing hypoxic neuronal injury due to lack of efficacy and potential neurotoxicity.