1. At the synaptic terminal, voltage-gated channels open, thereby stimulating the synaptic vesicles to release their neurotransmitters by exocytosis.

Ion

Explanation:

At the synaptic terminal, voltage-gated ion channels open, thereby stimulating the synaptic vesicles to release the neurotransmitters by exocytosis.

These ion channels are the signaling molecules in neurons. They are the transmembrane proteins that form ion channels. The membrane potential changes the conformation of the channel proteins that regulates their opening and closing. These channels play an important role in neurotransmitter release in presynaptic nerve endings.

For example - Ca²⁺ gated ion channel.