Final answer:
Glutamate is an example of an excitatory neurotransmitter.
Step-by-step explanation:
An example of an excitatory neurotransmitter is glutamate. Glutamate is the primary excitatory neurotransmitter in the central nervous system (CNS) and is responsible for fast excitatory neurotransmission. When glutamate is released at the synapse, it binds to receptors on the postsynaptic cell and opens ion channels, allowing cations like sodium to flow into the neuron. This depolarizes the postsynaptic membrane, making the neuron more likely to fire an action potential.