AMPA receptor: Difference between revisions
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<xmlns:texthelpns rwthpgen="1">AMPA receptors are </xmlns:texthelpns>[[Ligand-gated ion channel|Ligand gated ion channels]]<xmlns:texthelpns rwthpgen="1">.The ligand (signalling molecule) they are complementary to is a </xmlns:texthelpns>[[Glutamate|Glutamate]]<xmlns:texthelpns rwthpgen="1">which is the main excitatory </xmlns:texthelpns>[[Neurotransmitter|neurotransmitter]]<xmlns:texthelpns rwthpgen="1">in the </xmlns:texthelpns>[[Central nervous system|CNS]]<xmlns:texthelpns rwthpgen="1">, this means there is a high proportion of these AMPA receptors on postsynaptic neurons in the brain.</xmlns:texthelpns>< | <xmlns:texthelpns rwthpgen="1">AMPA receptors are </xmlns:texthelpns>[[Ligand-gated ion channel|Ligand gated ion channels]]<xmlns:texthelpns rwthpgen="1">.The ligand (signalling molecule) they are complementary to is a </xmlns:texthelpns>[[Glutamate|Glutamate]] <xmlns:texthelpns rwthpgen="1">which is the main excitatory </xmlns:texthelpns>[[Neurotransmitter|neurotransmitter]] <xmlns:texthelpns rwthpgen="1">in the </xmlns:texthelpns>[[Central nervous system|CNS]]<xmlns:texthelpns rwthpgen="1">, this means there is a high proportion of these AMPA receptors on postsynaptic neurons in the brain. </xmlns:texthelpns> | ||
<xmlns:texthelpns rwthpgen="1"></xmlns:texthelpns><xmlns:texthelpns rwthpgen="1">When Glutamate binds to AMPA receptors it causes a conformational change and the ion channel opens allowing Na+ ions to flood into the postsynaptic cell. </xmlns:texthelpns><xmlns:texthelpns rwthpgen="1">The increase in Na+ concentration causes depolarisation of the postsynaptic membrane generating an </xmlns:texthelpns>[[EPSP|EPSP]] <xmlns:texthelpns rwthpgen="1">( which if strong enough can go on to initiate an </xmlns:texthelpns>[[Action potential|action potential]] <xmlns:texthelpns rwthpgen="1">at the axon hillock).</xmlns:texthelpns><xmlns:texthelpns rwthpgen="1">Repetitive stimulation of these synapses in the brain can cause LTP (</xmlns:texthelpns>[[Long term potentiation|Long-term potentiation]]<xmlns:texthelpns rwthpgen="1">) , due to more Glutamate being released across the synaptic cleft binding to more AMPA receptors which leads to a higher influx of Na+ ions into the cell generating a stronger EPSP. </xmlns:texthelpns><xmlns:texthelpns rwthpgen="1">This strong depolarisation of the post-synaptic member aids to the activation of </xmlns:texthelpns>[[NMDA receptor|NMDA receptors]] <xmlns:texthelpns rwthpgen="1">( along with glutamate binding) which allow Ca2+ ions to enter the post synaptic cell.</xmlns:texthelpns><xmlns:texthelpns rwthpgen="1">This increase in Ca 2+ concentration can cause new AMPA receptors to be inserted in to the post-synaptic membrane increasing the sensitivity of the post-synaptic cell to Glutamate.</xmlns:texthelpns><xmlns:texthelpns rwthpgen="1"> </xmlns:texthelpns><ref>Bruce Alberts, e. a., 2008. Molecular Biology of the cell. 5th ed (pg 690). New York: Garland Science.</ref><br> | |||
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Revision as of 14:56, 9 November 2013
<xmlns:texthelpns rwthpgen="1">AMPA receptors are </xmlns:texthelpns>Ligand gated ion channels<xmlns:texthelpns rwthpgen="1">.The ligand (signalling molecule) they are complementary to is a </xmlns:texthelpns>Glutamate <xmlns:texthelpns rwthpgen="1">which is the main excitatory </xmlns:texthelpns>neurotransmitter <xmlns:texthelpns rwthpgen="1">in the </xmlns:texthelpns>CNS<xmlns:texthelpns rwthpgen="1">, this means there is a high proportion of these AMPA receptors on postsynaptic neurons in the brain. </xmlns:texthelpns>
<xmlns:texthelpns rwthpgen="1"></xmlns:texthelpns><xmlns:texthelpns rwthpgen="1">When Glutamate binds to AMPA receptors it causes a conformational change and the ion channel opens allowing Na+ ions to flood into the postsynaptic cell. </xmlns:texthelpns><xmlns:texthelpns rwthpgen="1">The increase in Na+ concentration causes depolarisation of the postsynaptic membrane generating an </xmlns:texthelpns>EPSP <xmlns:texthelpns rwthpgen="1">( which if strong enough can go on to initiate an </xmlns:texthelpns>action potential <xmlns:texthelpns rwthpgen="1">at the axon hillock).</xmlns:texthelpns><xmlns:texthelpns rwthpgen="1">Repetitive stimulation of these synapses in the brain can cause LTP (</xmlns:texthelpns>Long-term potentiation<xmlns:texthelpns rwthpgen="1">) , due to more Glutamate being released across the synaptic cleft binding to more AMPA receptors which leads to a higher influx of Na+ ions into the cell generating a stronger EPSP. </xmlns:texthelpns><xmlns:texthelpns rwthpgen="1">This strong depolarisation of the post-synaptic member aids to the activation of </xmlns:texthelpns>NMDA receptors <xmlns:texthelpns rwthpgen="1">( along with glutamate binding) which allow Ca2+ ions to enter the post synaptic cell.</xmlns:texthelpns><xmlns:texthelpns rwthpgen="1">This increase in Ca 2+ concentration can cause new AMPA receptors to be inserted in to the post-synaptic membrane increasing the sensitivity of the post-synaptic cell to Glutamate.</xmlns:texthelpns><xmlns:texthelpns rwthpgen="1"> </xmlns:texthelpns>[1]
References
- ↑ Bruce Alberts, e. a., 2008. Molecular Biology of the cell. 5th ed (pg 690). New York: Garland Science.