K+ and IPSP or EPSP

Question

You are studying the role of a newly discovered neurotransmitter. You find that there are receptors for this neurotransmitter on interneurons in the brain and that when it binds, it causes the opening of K+ What can we expect of the postsynaptic cells under influence of this neurotransmitter?

a) The postsynaptic cell will immediately undergo an action potential.

b) The postsynaptic cell will undergo an IPSP.

c) The postsynaptic cell will undergo an EPSP.

d) There will be no change to the membrane potential in the postsynaptic cell.

Answer 1

The answer is b).

There is naturally a higher concentration of K+ on the inside of the cell at rest. When the K+ ion channel opens, it allows K+ to flow out of the cell, making the inside of the cell more negatively charged. This will make it harder for the cell to reach the positive threshold to undergo an action potential.

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