What is neurotransmission?
Neuronal anatomy details the process of receiving and sending information from neighboring cells. Neuron axons send signals, while dendrites receive information from other cells.
Depending on the type of signal they release, neurons can be classified as either excitatory or inhibitory neurons. Other features that aid in neuronal classification include neuronal polarity, morphology, anatomical localization, protein expression profiles, and directional flow of information.
What are neurotransmitters and what do they do?
Neurotransmission from neurons and the extraneural system mediates the propagation of electrical signals through a series of intracellular events. The extracellular space between two cells is the synapse, so the source of the signal is the presynaptic cell and the receiving neuron is the postsynaptic cell.
Neurotransmitters can be classified as small molecules or neuropeptides. Synthesis of small neurotransmitters occurs locally - in the axon terminal, whereas neuropeptides are much larger than small molecules and are synthesized inside the cell. a neuromodulatory neurotransmitter is known to play a major role in mood and addiction, control of posture, and movement. Declines in dopamine expression in the brain are linked to muscle dysfunction in Parkinson's disease.
- An inhibitory neurotransmitter is known to stabilize mood and regulate sleep cycles.
- Anxiety is associated with extremely high levels of norepinephrine.
- Epinephrine: An excitatory neurotransmitter that raises heart rate and blood pressure to stimulate the body's "fight/flight" response.
How does neurotransmission occur?
Neurotransmitter release is dependent on changes in intracellular voltage, which are mediated by ligands and gated ion channels in presynaptic cells. Cell depolarization causes action potentials to propagate throughout the axon.
After crossing the synapse, the neurotransmitter binds to the postsynaptic receptor on the dendrite, followed by an excitatory or inhibitory response.
Enzymatic degradation of neurotransmitters that occur during transport and mediated recycling by the synaptic cleft to their original axon terminals, or transporter-mediated uptake by astrocytes terminates neurotransmission.
Neurotransmitter Glutamate
- In the central nervous system, glutamate is the excitatory neurotransmitter with the highest content and the widest distribution. It participates in the learning and memory functions of the brain by activating glutamate receptors on the postsynaptic membrane. Excitatory glutamate levels in the synaptic cleft must be tightly regulated to avoid glutamate excitotoxicity due to the overstimulation of glutamate receptors. Excitatory glutamate transporter 2 (hEAAT2), expressed on the plasma membrane of astrocytes, uses the transmembrane electrochemical gradient of transport ions and membrane potential as the driving force to transport about 90% of glutamate in the synaptic cleft to Clear in cells. hEAAT2 belongs to the SLC1A family protein, which has dual functions of glutamate transport and mediating anion conductance. When the protein is dysfunctional or impaired, it can lead to various neurological diseases such as epilepsy, Parkinson's disease, episodic ataxia, and amyotrophic lateral sclerosis, and is an important drug treatment target. Currently, there are no drugs targeting these proteins (EAATs) on the market. Therefore, the elucidation of the ligand-binding mode of the hEAAT2 protein will be of great significance for the treatment of hEAAT2-related neurological diseases.
Understanding the 7 Major Neurotransmitters
There are many kinds of neurotransmitters, let's focus on the main 7 of them. According to their different functions, they are divided into two different types.
1. glutamic acid
This amino acid is commonly found in your diet. It is an excitatory neurotransmitter that stimulates neurons to send out instructions. Glutamate is not only found in your diet, it is also found in 90% of synapses and serves as the main excitatory neurotransmitter in the central nervous system.
A small amount of glutamate can excite brain cells. When neurons are functioning normally, the glutamate released by the cell is picked up by glutamate transporter molecules. This ensures that glutamate levels in the synapses remain low.
Too much glutamate isn't necessarily good for your brain. Excess glutamate can make cells so excited that neurons can't bring energy down. This harmful state causes brain cells to become locked up and unable to function. Fortunately, there are transporters in the brain that protect your brain by removing excess glutamate after each action potential.
2. GABA (gamma-aminobutyric acid)
If glutamate is the most excitable chemical messenger, GABA is the other extreme. GABA is the main inhibitory neurotransmitter. It lowers activity in the central nervous system, blocking certain signals from the brain.
You need GABA to have a calming effect, to slow you down. It slows your heartbeat and lowers your blood pressure. GABA also helps you relax and sleep and has a great effect on reducing normal stress in your life.
3. dopamine
The most exciting neurotransmitter is dopamine. That's because it plays an important role in the brain's reward mechanisms.
When something rewarding happens, dopamine floods the synapses between neurons. That euphoria you feel when you reach a goal or complete a task is all thanks to dopamine. Dopamine perks up your brain, creating a pleasurable feeling.
Some drugs abuse the brain's reward mechanisms. They stimulate the brain to release excess dopamine, causing a temporary feeling of pleasure or high. But the aftermath of the dopamine high can be quite different, and you may feel blue, tired, and less interested in your favorite activities.
Drugs aren't the only ones that disrupt your brain's dopamine levels; addictive activities like video games, gambling, and shopping can all produce a similar high. The surge of dopamine in your brain can make breaking these habits difficult. So it's important to understand the functions of dopamine because these functions can help you restrain these behaviors.
4. adrenaline
If you've ever been frightened, you know the feeling of adrenaline. This neurotransmitter is responsible for your body's stress response.
Epinephrine is produced by the adrenal glands located above your kidneys.
Why do you need adrenaline when you won't be in a fight-or-flight scenario triggered by being chased by a predator? Because your everyday life is filled with similar but not life-or-death situations.
Adrenaline is your body's resistance mechanism to cope with stress. If you're running late and fear missing the flight, the adrenaline rushes your breathing and heartbeat to get you through security quickly.
5. serotonin
If your stomach doesn't accept the food you eat, serotonin helps the body get rid of it.
Rotten or spoiled food can make you sick because serotonin works when you eat potentially toxic food. It triggers your brain to make you feel sick and helps your bowels move food out of your body quickly.
Serotonin functions slightly differently in the brain. It greatly affects your mood, promoting feelings of well-being and joy. Serotonin also helps you sleep better and regulates your body's biological clock.
Serotonin can also sometimes be out of balance. When your brain doesn't produce enough serotonin, you can feel down, sleepless, and even confused and confused.
Conversely, it may be more dangerous if there is too much serotonin in the brain. It can cause paranoid delusions, impair your judgment, and negatively affect your memory. Therefore, it is necessary to protect the supply of serotonin in the brain to maintain this delicate balance.
6. Oxytocin
Let's clear up some of the mysteries about oxytocin first. This neurotransmitter is much more than a "love hormone." It does a lot more than this chemical messenger's cutesy reputation.
Oxytocin is produced in the hypothalamus of the brain and released through the pituitary gland, triggering a systemic response.
When a woman gives birth, oxytocin causes the walls of the uterus to contract. The same chemical messengers facilitate mother-child bonding in the immediate postpartum period. Oxytocin also acts by stimulating the mammary glands to secrete breast milk, which in turn promotes breastfeeding.
7. Acetylcholine
It's last on the list, but it was the first neurotransmitter discovered in humans. Acetylcholine is special because it directly affects your muscles.
Acetylcholine works at the neuron-muscle junction, where your nervous system meets your muscles. When acetylcholine is released from neurons, receptor proteins on muscle fibers receive it. The presence of acetylcholine triggers action potentials in muscle fibers. But acetylcholine doesn't send signals to the brain, it just makes your muscles contract.
Acetylcholine is at work every time you move a muscle, including involuntary activities like the beating of your heart or the contraction of the muscles that move food through your digestive tract.
Acetylcholine does more than move muscles. Your brain's learning and memory functions are also affected by this important neurotransmitter.
Apply Your Neurotransmitter Knowledge
- Now that you know how neurotransmitters work, let's think about how to effectively use them to support your health.
- Take a few minutes to thank the neurotransmitters in your body for their work. These chemical messengers allow your brain and body to communicate by helping everything from your heartbeat to breathing, digestion, and forming emotional bonds.
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