1. Synthesis, Transport an Recycling of the Neurotransmitters in general
Zsuzsanna Kotek

2. Life cycle of a neurotransmitter: 1.Synthesis and storage
Synthesis takes place in the pre-synaptic neuron.
Main cathegories of neurotransmitters:
Small molecule NTs: synthesized locally within the axon terminal
Large peptides NTs: synthesized in the cell body.
Once they are synthesized, neurotransmitters, both small molecules and neuropeptides are stored in vesicles within the axon terminal until an action potential arrives and they are released.

3. Life cycle of a neurotransmitter: 2-3. Release and Binding
Action Potencial arrives and the voltage gated Ca2+ channels open up. Due to the Calcium ion influx the vesicle’s membrane fuses with the pre-synaptic membrane and neurotransmitters are released into the synaptic cleft.
Neurotransmitters diffuse through the synaptic cleft and bind to the post-synaptic receptors, which causes the ion channels to open.

4. Life cycle of a neurotransmitter: 4.Inactivation
In order to avoid constant stimulation and to make the receptors available for other neurotransmitters:
Recycling
Breaked down by enzymes
Diffuse away

5. Sources: