Final answer:
The release of neurotransmitters is a key step in the neural transmission sequence that can lead to EPSPs or IPSPs, depending on the type of neurotransmitter and the receptors on the postsynaptic cell. Voltage-gated calcium channels facilitate the release of neurotransmitters by allowing synaptic vesicles to merge with the presynaptic membrane and release their contents.
Step-by-step explanation:
The release of neurotransmitters would likely precede an excitatory postsynaptic potential (EPSP) or an inhibitory postsynaptic potential (IPSP). When a neurotransmitter like acetylcholine is released at a synaptic junction, it can bind to receptors causing Na+ channels to open, allowing Na+ ions to enter the postsynaptic cell. This can cause depolarization, leading to an EPSP which makes the neuron more likely to fire an action potential. On the other hand, neurotransmitters such as GABA may cause the opening of Cl- channels, where Cl- ions enter the cell and lead to hyperpolarization, resulting in an IPSP making the neuron less likely to fire an action potential.
The importance of voltage-gated calcium channels in the release of neurotransmitters is crucial. When an action potential arrives at the axon terminal, the depolarization of the membrane leads to the opening of these channels, allowing Ca2+ ions to enter. This influx of calcium ions enables synaptic vesicles containing neurotransmitters to merge with the presynaptic membrane, releasing their content into the synaptic cleft through exocytosis.