The Definition of a Neurotransmitter
Nerve cells are arranged in networks that communicate information with one another through neurotransmission, which is the conduction of electrical messages from neuron to neuron. The electrochemical messages cross the synapses between neural cells by way of special chemical messengers called neurotransmitters.
Neurotransmitters are chemicals found and produced in the brain to allow the transmission of impulses from one nerve cell to the next across synapses. They aid in the conduction of information throughout the body. These chemicals fit into specific receptor cells embedded in the membrane of the dendrite that either fuel up or excite action in the cells (excitatory) or stop or inhibit an action (inhibitory).
The presence or absence of these neurotransmitters can directly or indirectly have an effect on neurons in a specific portion of the brain. Thus, the levels of these chemicals in the brain can have an effect on a person’s behavior.
The Mechanism of a Nerve Impulse
Nerve cell conduction or communication is an extremely rapid process that involves the following:
- The impulse moves through the nerve in a long and slender cellular part called the axon.
- As the impulse travels through the axon it travels the presynaptic membrane. It is in this area that neurotransmitters are released into the free space called the synaptic cleft.
- The receptors located in the postsynaptic membrane of another nearby neuron pick up the free-flowing neurotransmitters.
- The molecule is adapted in the next nerve cell and the impulse continues to the next nerve cell until the message is relayed throughout the body.
What happens after neurotransmitters send information?
After NT’s get released into the synapse and relay the message to the receptor cells, they are transported back from the synapse to the axon to be stored for later use, which is a process called reuptake. If the neurotransmitters don’t undergo reuptake, they will be metabolized or inactivated by enzymes, primarily monoamine oxidase.
Major Neurotransmitters
What do They have in Common?
- They all originated from the brain stem.
- None of the classic monoamines can cross the brain-blood barrier but amino acids i.e. glutamate can.
- You can’t eat them. Neurotransmitters are endogenous substances that originate and are processed from within.
- Neurotransmitters are the focus of mental illnesses and treatment.
What Makes them All Different? since the brain is like chemical stews, there are some overlapping but major differences in the functions of neurotransmitters:
- Serotonin (5ht)
- Norepinephrine (NE)
- Dopamine (DA)
- Acetylcholine (ACH)
- Glutamate (GLU) & GABA (y-aminobutyric acid)
Honorable Mentions
Histamine, hormones, & neuropeptides. Also, check out The Ultimate Guide to Neurotransmitters by Albert.
