Novel class of amino acid antagonists at non-N-methyl-D-aspartic acid excitatory amino acid receptors. Synthesis, in vitro and in vivo pharmacology, and neuroprotection
| Autor: | Nils Henrik Diemer, John Wm. Ferkany, Povl Krogsgaard-Larsen, David Beattie, David R. Curtis, Jørgen S. Johansen, Nielsen Elsebet Ostergaard, Bjarke Ebert, Ulf Madsen, Torben Bruhn |
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| Rok vydání: | 1991 |
| Předmět: |
Agonist
Male Receptor complex Kainic acid Stereochemistry medicine.drug_class Glycine N-Methyl-D-aspartic acid AMPA receptor In Vitro Techniques Tritium Binding Competitive Receptors N-Methyl-D-Aspartate chemistry.chemical_compound Structure-Activity Relationship Drug Discovery medicine Animals Quisqualic acid Ibotenic Acid alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid chemistry.chemical_classification Cerebral Cortex Neurons Molecular Structure Brain Rats Inbred Strains Isoxazoles Amino acid Rats chemistry Molecular Medicine NMDA receptor Autoradiography Indicators and Reagents Dizocilpine Maleate Propionates |
| Zdroj: | Journal of medicinal chemistry. 34(1) |
| ISSN: | 0022-2623 |
| Popis: | The isoxazole amino acid 2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl) propionic acid (AMPA) (1), which is a highly selective agonist at the AMPA subtype of excitatory amino acid (EAA) receptors, has been used as a lead for the development of two novel EAA receptor antagonists. One of the compounds, 2-amino-3-[3-(carboxymethoxy)-5-methylisoxazol-4-yl]propionic acid (AMOA, 7), was synthesized via O-alkylation by ethyl chloroacetate of the amino acid protected AMPA derivative 4. The other compound, 2-amino-3-[2-(3-hydroxy-5-methylisoxazol-4-yl)-methyl-5-methyl-3-+ ++oxoisoxazolin -4-yl]propionic acid (AMNH, 14) was synthesized with use of 4-(chloromethyl)-3-methoxy-5-methylisoxazole (8) as the starting material. The intermediate 4-(chloromethyl)-2-(3-methoxy-5-methylisoxazol-4-yl)methyl-5-me thylisoxazolin- 3-one (11) was converted into the acetamidomalonate (12), which was stepwise deprotected to give 14. Compounds 7 and 14 were stable in aqueous solution at pH values close to physiological pH. Neither 7 nor 14 showed detectable affinities for the receptor, ion channel, or modulatory sites of the N-methyl-D-aspartic acid (NMDA) receptor complex. Quantitative receptor autoradiographic and conventional binding techniques were used to study the affinities of 7 and 14 for non-NMDA receptor sites. Both compounds were inhibitors of the binding of [3H]AMPA (IC50 = 90 and 29 microM, respectively). Compounds 14 and 7 were both very weak inhibitors of the high-affinity binding of radioactive kainic acid [( 3H]KAIN). Compound 14, but not 7, was, however, shown to be an inhibitor of low-affinity [3H]KAIN binding (IC50 = 40 microM) as determined in the presence of 100 mM calcium chloride. In the rat cortical slice preparation, 7 was shown to antagonize excitation induced by 1 with some selectivity, whereas 14 proved to be a rather selective antagonist of KAIN-induced excitation. Both antagonists showed very weak effects on the excitatory effects of NMDA. Compound 7 was a poor antagonist of excitation by quisqualic acid (2), whereas 14 did not affect excitation by this nonselective AMPA receptor agonist. On cat spinal neurones, both 7 and 14 reduced excitations by 1 and KAIN, but, again, the excitatory effects of 2 were much less sensitive. Compound 14 and, in particular, 7 effectively protected rat striatal neurones against the neurotoxic effects of KAIN, whereas the toxic effects of 1 were reduced only by 7. Neither antagonist showed protection against the cell damage caused by intrastriatal injection of the NMDA agonist quinolinic acid.(ABSTRACT TRUNCATED AT 400 WORDS) |
| Databáze: | OpenAIRE |
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