Changes in the interaction between neurons or neural plasticity occur throughout

Question

Changes in the interaction between neurons or neural plasticity occur throughout the nervous system. In particular, it is believed that synaptic plasticity in the hippocampus is critical for storing specific types of information that are involved in the psychological process of memory. There is extensive evidence indicating that specific glutamate receptors at asymmetric/excitatory synapses are involves in specific aspects of acquisition and maintenance/expression of synaptic plasticity.

Describe the roles of the NMDA and AMPA receptors in synaptic plasticity within in the hippocampus. Your answer should address the nature of the input necessary to induce synaptic plasticity and how each of these receptors contribute to that process, including a brief description of downstream signaling. As well as, attributes of these receptors that allow them to perform specific roles in synaptic plasticity

Explanation / Answer

In the mammalian central nervous system, excitatory glutamatergic synapses harness neurotransmission that is mediated by ion flow through -amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs)and NMDA. AMPARs,and NMDAs which are enriched in the postsynaptic membrane on dendritic spines, are highly dynamic, and shuttle in and out of synapses in an activity-dependent manner. Changes in their number, subunit composition, phosphorylation state, and accessory proteins can all regulate AMPARs and thus modify synaptic strength and support cellular forms of learning. AMPARs are tetrameric, cation-permeable ionotropic glutamate receptors, and are expressed throughout the brain The four AMPAR subunits (GluA1–GluA4) are encoded by the genes GRIA1-GRIA4, and are assembled as dimers-of-dimers to form the hetero-tetrameric receptors although homo-tetrameric receptors have been reported .Upon binding of glutamate, the pore opening allows the influx of Na+ ions (along with K+ efflux) to depolarize the postsynaptic compartment; however, depending on the subunit composition and the RNA editing, AMPARs also permit Ca2+-influx, which has important consequences for plasticity by engaging Ca2+-dependent signaling events.

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