Experiment Results
Predict Question:
Predict Question 1: You have just observed that each action potential in a burst can trigger additional neurotransmitter
release. If calcium ions are removed from the extracellular solution, what will happen to neurotransmitter release at the axon
terminal?
Your answer : c. There will be less neurotransmitter release.
Predict Question 2: What will happen to neurotransmitter release when low amounts of calcium are added back to the
extracellular solution?
Your answer : b. Neurotransmitter release will increase a small amount.
Predict Question 3: What will happen to neurotransmitter release when magnesium is added to the extracellular solution?
Your answer : d. Neurotransmitter release will be greater than in the control solution.
Stop & Think Questions:
Why does the stimulus intensity affect the amount of neurotransmitter release at the axon terminal?
You correctly answered: d. Both a and b are correct.
Why is there no neurotransmitter release from the axon terminal when there are no calcium ions in the extracellular
solution?
You correctly answered: c. Exocytosis of the synaptic vesicles is calcium dependent.
Why did the high intensity stimulation fail to trigger the same amount of neurotransmitter release in the presence of
extracellular Mg2+ as in the control extracellular solution?
You correctly answered: a. Mg2+ blocks the calcium channels in the axon terminal.
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