Question

You are recording signals from a postsynaptic neuron that contains only one type of ionotropic receptor (and no other receptors of any kind). Your goal is to determine the reversal potential for this type of receptor. When you hold the membrane potential at -50 mV and activate these receptors, you observe that this causes IPSCs. Based on this information, what can you conclude about the reversal potential (E_rev) for these receptors? (Assume that the ion concentrations inside and outside this neuron the same as those of typical neurons.)

a. E_rev for this receptor is more positive than -50 mV

b. E_rev for this receptor is more negative than -50 mV

c. Nothing can be concluded about E_rev for this receptor based only on the information given

Answer 1

ANSWER :-

1. There is confusion regarding IPSC which should have been Inhibitory post synaptic potential. When IPSP occurs, there is definately a decrease in value such that the membrane potential becomes more negative and thus it will migrate to a point after which it will try to come back to its reversal potential at which there will be no net movement of any ions taking into consideration action potential is not happening.
2. So, this indicates the reversal potential to be more negative than the value of (-50 mV) which may act as the resting membrane potential.
3. So, option 'A' must be the most appropriate answer.

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