Summary
Chemical messengers like dopamine, serotonin and acetylcholine released across synapses.
In depth
Acetylcholine (muscle, memory), dopamine (reward, movement), serotonin (mood), noradrenaline (alertness), GABA (main inhibitory) and glutamate (main excitatory). Removed by reuptake or enzymes. Many drugs and toxins act at synapses.
Transmitters bind receptors producing fast (ionotropic) or modulatory (metabotropic) effects. Co-transmission is common. Cleanup prevents continuous stimulation.
Key idea: one transmitter can have different effects on different receptors.
Over 100 are known, in classes: amino acids (glutamate, GABA, glycine), monoamines (dopamine, noradrenaline, adrenaline, serotonin, histamine), acetylcholine, peptides (substance P, endorphins, oxytocin), purines (ATP, adenosine) and gases (nitric oxide). Receptors are ionotropic (fast, ligand-gated channels) or metabotropic (slower, G protein-coupled). Termination is by reuptake (transporters), enzymatic breakdown (acetylcholinesterase, MAO, COMT) or diffusion.
Imbalances relate to disease: dopamine in Parkinson disease and psychosis, serotonin in depression, glutamate excitotoxicity in stroke, GABA in epilepsy and anxiety, and acetylcholine in Alzheimer disease and myasthenia gravis. Otto Loewi showed chemical transmission in 1921 using frog hearts.
Frequently asked questions
What is Neurotransmitters?
Chemical messengers like dopamine, serotonin and acetylcholine released across synapses.
Which area of biology covers Neurotransmitters, and how advanced is it?
Neurotransmitters is one of the 54 topics in Neuroscience. It is rated Beginner, so it suits learners who are starting out in biology. Related topics in this area include Synaptic Transmission, Neuropharmacology, Excitatory and Inhibitory Synapses.
Why does Neurotransmitters matter?
Most psychiatric and neurological drugs work on neurotransmitter systems.
Can you give an example of Neurotransmitters?
Nerve gases inhibit acetylcholinesterase, causing continuous stimulation.
What should I learn before Neurotransmitters?
Neurotransmitters is a Beginner topic, so no earlier topic is required. Other Beginner topics in Neuroscience that pair well with it include Nervous System, Neuron, Central and Peripheral Nervous Systems.
What topics are related to Neurotransmitters?
The closest topics to Neurotransmitters are Synaptic Transmission, Neuropharmacology, Excitatory and Inhibitory Synapses, NMDA Receptors. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Neurotransmitters?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Neurotransmitters. To practise the whole of Neuroscience, use the Neuroscience quiz.
How is Neurotransmitters different from Synaptic Transmission?
Neurotransmitters: Chemical messengers like dopamine, serotonin and acetylcholine released across synapses. Synaptic Transmission: An action potential triggers calcium entry, vesicle release of transmitter and receptor binding on the postsynaptic cell. Read both side by side and note what each one explains.
How should I study Neurotransmitters step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Synaptic Transmission and explain the difference aloud. Finally, take the Neuroscience quiz and come back to this page for any question you miss.