Question

Name the three ionotropic glutamate receptors in the brain. For each, identify the ions that move to create the depolarizing effects. What effects does the drug NBQX have on these receptors and on behavior?

Answer 1

Three ionotropic receptors in the brain include NMDA (N-methyl D-aspartate) receptors, alpha-amino 3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors and kainate (KA) receptors

Research shows that glutamate receptors are present in CNS glial cells as well as neurons. These glutamate receptors are suggested to play a role in modulating gene expression in glial cells, both during the proliferation and differentiation of glial precursor cells in brain development and in mature glial cells.

AMPA receptors are the main charge carriers during basal transmission, permitting influx of sodium ions to depolarise the postsynaptic membrane.

Calcium influx through NMDA receptors leads to persistent modifications in the strength of synaptic transmission.

The ion channel formed by kainate receptors is permeable to sodium and potassium ions.

Glutamate is the major excitatory neurotransmitter in central nervous system (CNS) and as such the glutamate receptors play a vital role in the mediation of excitatory synaptic transmission. This process is the means by which cells in the brain (neurons) communicate with each other. NBQX acts as antagonist of AMPA and KA glutamate receptors. The receptor antagonist blocks the actions of glutamate which is an amino acid that is a particularly potent nerve cell killer. The antagonists like NBQX block a receptor group to glutamate. Thus it is used to counter glutamate excitotoxicity and it has got anticonvulsant properties.