| Abstract | It is widely held that a glutamate-like toxin that resembles N-methyl-D-aspartate may be responsible for the death of nerve cells seen after severe neurological insults including stroke, seizures, and degenerative disorders, such as Huntington disease, Alzheimer disease, and the amyotrophic lateral sclerosis-parkinsonism-dementia complex found on Guam. One puzzling fact about these maladies is the differential vulnerability of specific groups of neurons peculiar to each condition. We report here that an identified population of central neurons, rat retinal ganglion cells, are resistant to the neurotoxic effects of millimolar concentrations of glutamate under otherwise normal culture conditions. Patch-clamp experiments show that this resistance is associated with a very small ionic current response to N-methyl-D-aspartate. Varying the ionic milieu by increasing the extracellular Ca2+ concentration, however, results in a striking increase in glutamate-induced cell death in this population. Under these conditions, Mg2+ or the amino acid antagonist MK-801 [(+)-5-methyl-10,11-dihydro-5H-dibenzo-(alpha,gamma)-cyclohepten-5 ,10-imine maleate], blockers of N-methyl-D-aspartate receptor-coupled ion channels, completely abrogate the lethal effects of glutamate. These findings strongly suggest that Ca2+ entry through N-methyl-D-aspartate-activated channels is responsible for this type of neuronal death and suggest strategies that may be clinically useful in the treatment of various neurological disorders. |
| Authors | J S Hahn, E Aizenman, S A Lipton
(Affiliation: Department of Neurology, Children's Hospital, Boston, MA.)
|
| Journal | Proceedings of the National Academy of Sciences of the United States of America
(Proc Natl Acad Sci U S A)
Vol. 85
Issue 17
Pg. 6556-60
(Sep 1988)
ISSN: 0027-8424 UNITED STATES |
| PMID | 2901101
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)
|
| Chemical References |
- Anticonvulsants
- Dibenzocycloheptenes
- Glutamates
- Aspartic Acid
- Glutamic Acid
- N-Methylaspartate
- Calcium
- Dizocilpine Maleate
|
| Topics |
- Animals
- Anticonvulsants
(pharmacology)
- Aspartic Acid
(analogs & derivatives, antagonists & inhibitors)
- Calcium
(pharmacology)
- Cell Survival
(drug effects)
- Cells, Cultured
- Dibenzocycloheptenes
(pharmacology)
- Dizocilpine Maleate
- Glutamates
(pharmacology, toxicity)
- Glutamic Acid
- N-Methylaspartate
- Rats
- Retina
(cytology)
- Retinal Ganglion Cells
(cytology, drug effects)
|
