This is a neuroscience question. Any idea how to go about it...? A cell with nor

Question

This is a neuroscience question. Any idea how to go about it...?

A cell with normal resting membrane potential of -70 mV has Intracellular and extracellular Ion concentrations as shown at left below. The cell which was in situ, was voltage-clamped at -90 mv. After a couple of minutes, the investigators added glycine, producing the trace to the right. Notice the difference in time scales. The membrane was impermeable to anions other than chloride ions (PA = 0). In what direction did current flow through the cell membrane after adding glycine? What ion or ions was/were responsible for the observed current? Cite all evidence that led you to your conclusions. Why do suppose the channels began to close, starting around 2.5 msec?

Explanation / Answer

The current would flow in the outward direction through the cell membrane after addition of glycine as glycine results in hyperpolarization of the membrane followed by depolarization.Based on these I-V relations, Egly was determined at different times during the glycine action, because the value of Egly depended on the response phase . A strong shift of the current reversal from negative value to positive value(as shown in the graph on right side) indicating some change in the distribution of the ions involved in this response.

The ions responsible for the observed current are the glycine induced Cl- ions.

The channels began to close because after increase in posutive value of current and reaching a peak the current gradually decreases and reaches the 0 value.this is due to hyperpolarization of the membrane and probably induced by inward flow of Cl- ions and increase in its intracellular concentration.

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