(RS)-AMPA

An antagonist of glutamate metabotropic receptors, (RS)-alpha-methyl-4-carboxyphenylglycine, prevents the LTP-related increase in postsynaptic AMPA sensitivity in hippocampal slices.[Pubmed:7694173]

Neuropharmacology. 1993 Sep;32(9):933-5.

(RS)-alpha-methyl-4-carboxyphenylglycine (MCPG), a compound which selectively antagonizes metabotropic glutamate receptors (mGlu-R), presents the LTP of field excitatory postsynaptic potentials (fEPSP) as well as the tetanus-induced increase in AMPA-evoked responses (fPRs) in the CA1 region of hippocampal slices. This effects of MCPG provide evidence for the involvement of mGlu-Rs in mechanisms underlying the postsynaptic maintenance of LTP, which appears to be mediated, at least partially, by an increase in sensitivity and/or number of postsynaptic AMPA receptors.

Promiscuous interactions between AMPA-Rs and MAGUKs.[Pubmed:17046684]

Neuron. 2006 Oct 19;52(2):222-4.

What controls the number of AMPA receptors at excitatory synapses? MAGUKs are known to play a critical role in this process, but which ones are involved and when has been contentious. In this issue of Neuron, Elias et al. have elucidated the roles of three MAGUKs, PSD-95, PSD-93, and SAP-102, in the targeting of AMPA receptors to synapses in hippocampal neurons.

Effects of (RS)-3,4-DCPG, a mixed AMPA antagonist/mGluR8 agonist, on aggressive behavior in mice.[Pubmed:23034312]

Rev Psiquiatr Salud Ment. 2009 Jul;2(3):133-7.

INTRODUCTION: Ionotropic and metabotropic (mGlu) receptors of glutamate have been suggested to be involved in the modulation of aggression. Thus, recent studies found reduced aggression in AMPA-type glutamate receptor GluR-A subunit-deficient mice. Likewise, mGlu1 and 5 receptors have also been implicated in aggression regulation. (RS)-3,4-DCPG is a mixed antagonist of AMPA receptors and an agonist of mGluR8. The AMPA antagonist activity of this compound is determined by its R isomer while the S isomer is responsible for its mGluR8 agonistic properties. METHODS: We analyzed the effects of (RS)-3,4-DCPG (5, 10 and 20mg/kg, ip) on agonistic encounters between male mice. Individually housed mice were exposed to anosmic opponents 30 min after drug administration. Ten min of dyadic interactions were staged between a singly housed and an anosmic mouse in a neutral area. The encounters were videotaped and the accumulated time allocated by subjects to 10 broad behavioral categories was estimated using an ethologically based analysis. RESULTS AND CONCLUSIONS: The results indicated that (RS)-3,4-DCPG produced no significant behavioral changes, suggesting that antagonism of AMPA receptors by the R isomer and stimulation of mGluR8 by the S isomer do not act synergistically on aggression in the racemic form of 3,4-DCPG.

The binding of [3H]AMPA, a structural analogue of glutamic acid, to rat brain membranes.[Pubmed:6125564]

J Neurochem. 1982 Jan;38(1):173-8.

Binding of [3H]AMPA to rat brain membranes was investigated. The binding was saturable and reversible at physiological pH. Computer-aided Scatchard analysis of the binding data, as determined by using L-glutamic acid (L-GLU) to define nonspecific binding, suggested the presence of two independent binding sites, with KDS of 9 and 2440 nM, respectively. Additional freezing, thawing and washing sequences gave membranes with only one binding site, with a KD of 278 nM. [3H]AMPA binding exhibited the highest level in striatal membranes. A series of analogues of GLU and aspartic acid (ASP) were tested as inhibitors of [3H]AMPA binding. L-ASP and compounds which interact predominantly with N-methyl-D-aspartic acid (NMDA) receptor sites were inactive as inhibitors of [3H]AMPA binding, whereas L-GLU and compounds which interact predominantly with glutamic acid diethyl ester receptor sites were inhibitors with the same order of potency as that shown by the excitatory action in vivo. The result suggests that [3H]AMPA might represent binding to an excitatory GLU receptor.