A sensory neuron is bathed in tetraammonium chloride and MgCl2, and then the voltage clamp is changed from -70 millivolts to -5 millivolts. You would expect to see:

hello your question lacks the options related attached below is the complete question

answer :

A brief positive current inward due to sodium entry through voltage gated sodium channels ( Option 4 )

Explanation:

What you would expect to see following the bathing of a sensory neuron in  tetra ammonium chloride and MgCl2, given that the voltage clamp moves from -70 to -5 mV is A brief positive current inward due to sodium entry through voltage gated sodium channels.

This is because as Cl^- enters the cells it causes the entrance of  Na^+ into the cell ( i.e. voltage gated Na^+ ions channels will open ) hence the mixture will cause a lower negative membrane potential to be present .