Abstract
The potency of l-glutamate in enhancing [3H]MK-801 binding to N-methyl-d-aspartate (NMDA) receptor ion channels was evaluated by quantitative autoradiography. In the presence of saturating concentrations of spermine, glycine and 20 μM d-2-amino-5-phosphonopentanoate (d-AP5), low concentrations of l-glutamate selectively increased [3H]MK-801 binding in the medial striatum and dorsal lateral septum. In comparison to these regions, EC50 values for l-glutamate stimulation of [3H]MK-801 binding were significantly higher in the cerebral cortex and thalamus. Regions displaying greater sensitivity to l-glutamate correlate to those regions where NMDA receptors are preferentially labelled by l-[3H]glutamate; regions less sensitive to l-glutamate correspond to regions selectively labelled by the NMDA antagonist [3H]CPP ([3H]3-((+)-2-carboxypiperazin-4-yl)-propyl-1-phosphonate). Since l-glutamate stimulation of [3H]MK-801 binding appears to reflect channel activation, these results suggest that it is possible to pharmacologically (or pathologically) activate anatomically-distinct subpopulations of NMDA receptors.
Original language | English (US) |
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Pages (from-to) | 21-24 |
Number of pages | 4 |
Journal | Neuroscience Letters |
Volume | 122 |
Issue number | 1 |
DOIs | |
State | Published - Jan 14 1991 |
Keywords
- Autoradiography
- Excitatory amino acid
- Glycine
- MK-801
- NMDA receptor
- Polyamine
ASJC Scopus subject areas
- Neuroscience(all)