Electrical Signaling in Neurons (4C) Practice Test
•15 QuestionsA study examines synaptic transmission at a single chemical synapse between one presynaptic neuron and one postsynaptic neuron. An action potential arriving at the presynaptic terminal opens voltage-gated Ca$^{2+}$ channels, allowing Ca$^{2+}$ influx that triggers vesicle fusion and neurotransmitter release. The neurotransmitter binds ligand-gated cation channels on the postsynaptic membrane, producing an excitatory postsynaptic potential (EPSP). In one condition, extracellular Ca$^{2+}$ is reduced from 2.0 mM to 0.2 mM while all other ions are unchanged, and the presynaptic action potential waveform is assumed unchanged.
Based on the scenario, which outcome is most consistent with synaptic transmission when extracellular Ca$^{2+}$ is lowered?
A study examines synaptic transmission at a single chemical synapse between one presynaptic neuron and one postsynaptic neuron. An action potential arriving at the presynaptic terminal opens voltage-gated Ca$^{2+}$ channels, allowing Ca$^{2+}$ influx that triggers vesicle fusion and neurotransmitter release. The neurotransmitter binds ligand-gated cation channels on the postsynaptic membrane, producing an excitatory postsynaptic potential (EPSP). In one condition, extracellular Ca$^{2+}$ is reduced from 2.0 mM to 0.2 mM while all other ions are unchanged, and the presynaptic action potential waveform is assumed unchanged.
Based on the scenario, which outcome is most consistent with synaptic transmission when extracellular Ca$^{2+}$ is lowered?