Final answer:
Neurotransmitters such as glutamate and acetylcholine typically cause depolarization, making neurons more likely to fire, while GABA and glycine cause hyperpolarization, inhibiting neuron firing.
Step-by-step explanation:
The question pertains to neurotransmitters that are involved in either excitatory or inhibitory synaptic actions, specifically in relation to whether they cause a hyperpolarizing or depolarizing effect on the postsynaptic neuron. The neurotransmitters in question include amino acids like glutamate, which is known to cause depolarization of the postsynaptic cell due to it being an excitatory neurotransmitter. On the other hand, GABA (gamma-aminobutyric acid) and glycine are known to cause hyperpolarization because they are inhibitory neurotransmitters. When acetylcholine is released in neuromuscular junctions, it causes depolarization as well. Other neurotransmitters like dopamine, serotonin, and norepinephrine can have varying effects based on the type of receptors they interact with.