The role of calcium ions (Ca²⁺) in synaptic transmission is to
A)bind neurotransmitter molecules to the postsynaptic membrane.
B)mediate the release of neurotransmitter molecules from the presynaptic neuron.
C)repolarize the postsynaptic cell after transmission has been completed.
D)increase the activity of the sodium-potassium pumps in the presynaptic cell.

Question

Quizplus · Accepted Answer

Calcium ions play a key role in synaptic transmission by mediating the release of neurotransmitter molecules from the presynaptic neuron into the synaptic cleft, where they can bind to receptors on the postsynaptic membrane and transmit a signal. Once the action potential reaches the presynaptic terminal, voltage-gated calcium channels open, allowing calcium ions to flow into the terminal. The increased concentration of calcium triggers the exocytosis of synaptic vesicles containing neurotransmitter molecules, which diffuse across the synaptic cleft and bind to receptors on the postsynaptic membrane. Therefore, option B is the most appropriate choice.

The Role of Calcium Ions (Ca²⁺) in Synaptic Transmission Is