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Multiple Choice
In posttetanic potentiation, which of the following is released to enhance synaptic transmission?
A
Dopamine
B
Acetylcholinesterase
C
Calcium ions ($\mathrm{Ca^{2+}}$)
D
Glucose
Verified step by step guidance
1
Understand the concept of posttetanic potentiation: It is a phenomenon where synaptic transmission is temporarily enhanced following a high-frequency stimulation of a neuron. This is due to changes in the presynaptic terminal that increase neurotransmitter release.
Identify the key factor involved in enhancing synaptic transmission: During posttetanic potentiation, the accumulation of calcium ions ($\mathrm{Ca^{2+}}$) in the presynaptic terminal plays a critical role.
Explain the role of calcium ions ($\mathrm{Ca^{2+}}$): High-frequency stimulation leads to an influx of $\mathrm{Ca^{2+}}$ into the presynaptic terminal. This elevated $\mathrm{Ca^{2+}}$ concentration enhances the release of neurotransmitters into the synaptic cleft.
Clarify why the other options are incorrect: Dopamine is a neurotransmitter but is not directly involved in posttetanic potentiation. Acetylcholinesterase is an enzyme that breaks down acetylcholine and does not enhance synaptic transmission. Glucose is a source of energy but does not directly influence synaptic potentiation.
Conclude that calcium ions ($\mathrm{Ca^{2+}}$) are the correct answer because they are the key factor responsible for enhancing synaptic transmission during posttetanic potentiation.