NMDA receptors play a crucial role in synaptic plasticity, learning, and memory. One of their unique features is the presence of a magnesium (Mg²⁺) block that prevents ion flow through the receptor channel when the postsynaptic membrane is at resting potential. Imagine that the mechanism of magnesium blockage in NMDA receptors did not exist. Which of the following consequences would you expect to occur? Choose two correct answers. Group of answer choicesNMDA receptors would become less responsive to glutamate, leading to a reduction in synaptic plasticity and learning.The absence of the magnesium block would allow calcium ions to flow into the postsynaptic neuron more easily, potentially leading to excitotoxicity and cell death.NMDA receptors would no longer require both glutamate binding and postsynaptic depolarization to become activated, losing their coincidence detection property.Long-term potentiation (LTP) would be enhanced, as the magnesium block normally limits the induction of LTP.The lack of a magnesium block would prevent NMDA receptors from contributing to the generation of NMDA receptor-dependent long-term depression (LTD).
Question
NMDA receptors play a crucial role in synaptic plasticity, learning, and memory. One of their unique features is the presence of a magnesium (Mg²⁺) block that prevents ion flow through the receptor channel when the postsynaptic membrane is at resting potential. Imagine that the mechanism of magnesium blockage in NMDA receptors did not exist. Which of the following consequences would you expect to occur? Choose two correct answers. Group of answer choicesNMDA receptors would become less responsive to glutamate, leading to a reduction in synaptic plasticity and learning.The absence of the magnesium block would allow calcium ions to flow into the postsynaptic neuron more easily, potentially leading to excitotoxicity and cell death.NMDA receptors would no longer require both glutamate binding and postsynaptic depolarization to become activated, losing their coincidence detection property.Long-term potentiation (LTP) would be enhanced, as the magnesium block normally limits the induction of LTP.The lack of a magnesium block would prevent NMDA receptors from contributing to the generation of NMDA receptor-dependent long-term depression (LTD).
Solution
The two correct answers would be:
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"The absence of the magnesium block would allow calcium ions to flow into the postsynaptic neuron more easily, potentially leading to excitotoxicity and cell death." This is because the magnesium block normally prevents excessive calcium influx, which can be harmful to the cell.
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"NMDA receptors would no longer require both glutamate binding and postsynaptic depolarization to become activated, losing their coincidence detection property." This is because the magnesium block is removed during depolarization, allowing the receptor to respond to glutamate. Without the block, the receptor could be activated by glutamate alone, without the need for depolarization.
Similar Questions
An NMDA receptor channel is blocked by magnesium unlessGroup of answer choicescalcium binds to autoreceptors on the presynaptic neuronglutamate binds to all the receptors on the dendritethe postsynaptic neuron is already hyperpolarizedCA3 field pyramidal cell is repeatedly stimulatedthe postsynaptic membrane is already depolarized
What is the immediate consequence of Mg2+ blockade removal from the NMDA receptors?Group of answer choicesPostsynaptic EPSPCa2+ influx into the presynaptic terminalCa2+ influx into the postsynaptic terminalGlutamate binding to its receptors
A secondary consequence of NMDA receptor antagonism is _______ presynaptic glutamate release, which may result from _______ of receptors on inhibitory GABAergic interneurons that innervate the cortical neurons. Group of answer choicesdecreased; blockadedecreased; openingincreased; blockadeincreased; opening
PCP and ketamine act on the postsynaptic cell by Group of answer choicesblocking the NMDA receptor at the glutamate site.stimulating the receptor where NMDA normally binds.acting as a competitive antagonist at the NMDA receptor.acting as an uncompetitive antagonist at the NMDA receptor.
Long-term potentiation:Group of answer choicesalways exhibits associativityalways requires protein synthesis for inductionalways results in increased excitatory post-synaptic potentialsalways involves NMDA receptorsis only found in hippocampus
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