Neurotransmitters play an important role in neural communication. They are chemical messengers that carry messages between nerve cells (neurons) and other cells in your body, influencing everything from mood to involuntary movements. This process is generally referred to as neurotransmission or synaptic transmission. Show
Specifically, excitatory neurotransmitters have excitatory effects on the neuron. This means they increase the likelihood that the neuron will fire a signal called an action potential in the receiving neuron. Neurotransmitters can act in predictable ways, but they can be affected by drugs, disease, and interaction with other chemical messengers. To send messages throughout the body, neurons need to transmit signals to communicate with one another. But there is no physical connection with each other, just a minuscule gap. This junction between two nerve cells is called a synapse. To communicate with the next cell, a neuron sends a signal across the synapse by diffusion of a neurotransmitter. Neurotransmitters affect neurons in one of three ways: they can be excitatory, inhibitory, or modulatory. An excitatory transmitter generates a signal called an action potential in the receiving neuron. An inhibitory transmitter prevents it. Neuromodulators regulate groups of neurons.
Some neurotransmitters, such as dopamine, depending on the receptors present, create both excitatory and inhibitory effects. The most common and clearly understood types of excitatory neurotransmitters include: AcetylcholineThis is an excitatory neurotransmitter that is found throughout the nervous system. One of its many functions is muscle stimulation, including those of the gastrointestinal system and the autonomic nervous system. Are you familiar with cosmetic Botox injections? They’re used to eliminate wrinkles by temporarily paralyzing certain muscles. This procedure uses botulinum toxin to freeze the muscles in place by preventing neurons in the area from releasing acetylcholine. EpinephrineAlso called adrenaline, epinephrine is an excitatory neurotransmitter produced by the adrenal glands. It is released into the bloodstream to prepare your body for dangerous situations by increasing your heart rate, blood pressure, and glucose production. Are you familiar with the fight-or-flight response? Adrenaline helps your nervous and endocrine systems prepare for extreme situations in which you might be making a fight-or-flight decision. GlutamateThis is the most common neurotransmitter in the central nervous system. It is an excitatory neurotransmitter and usually ensures balance with the effects of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter. HistamineThis is an excitatory neurotransmitter primarily involved in inflammatory responses, vasodilation, and the regulation of your immune response to foreign bodies such as allergens. DopamineDopamine has effects that are both excitatory and inhibitory. It is associated with reward mechanisms in the brain. Drugs such as cocaine, heroin, and alcohol can temporarily increase its levels in the blood. This increase can lead to nerve cells firing abnormally that can result in intoxication along with consciousness and focus issues. A typical secretion of dopamine in your bloodstream can contribute to motivation. Also called noradrenaline, norepinephrine is the primary neurotransmitter in the sympathetic nervous system where it works to control heart rate, blood pressure, liver function, and other functions. Gamma-aminobutyric acidAlso known as GABA, gamma-aminobutyric acid is an inhibitory neurotransmitter that acts as a brake to the excitatory neurotransmitters. GABA has wide distribution in the brain and has a major role in reducing neuronal excitability throughout the nervous system. SerotoninSerotonin is an inhibitory neurotransmitter that is involved in emotion and mood, balancing excessive excitatory neurotransmitter effects in your brain. Serotonin also regulates processes, such as sleep cycle, carbohydrate cravings, food digestion, and pain control. There are billions of neurotransmitter molecules working constantly to keep your brain functioning and managing everything from your breathing to your heartbeat to your ability to concentrate. Understanding the way that nerve cells communicate, as well as how increases and decreases in neurotransmitters affect our physical and mental well-being, helps researchers and doctors find ways to make us happier and healthier.
Neurotransmitters are your body’s chemical messengers. They carry messages from one nerve cell across a space to the next nerve, muscle or gland cell. These messages help you move your limbs, feel sensations, keep your heart beating, and take in and respond to all information your body receives from other internal parts of your body and your environment.
Neurotransmitters carry chemical signals (“messages”) from one neuron (nerve cell) to the next target cell. Neurotransmitters are chemical messengers that your body can’t function without. Their job is to carry chemical signals (“messages”) from one neuron (nerve cell) to the next target cell. The next target cell can be another nerve cell, a muscle cell or a gland. Your body has a vast network of nerves (your nervous system) that send and receive electrical signals from nerve cells and their target cells all over your body. Your nervous system controls everything from your mind to your muscles, as well as organ functions. In other words, nerves are involved in everything you do, think and feel. Your nerve cells send and receive information from all body sources. This constant feedback is essential to your body’s optimal function. What body functions do nerves and neurotransmitters help control?Your nervous system controls such functions as your:
How do neurotransmitters work?You have billions of nerve cells in your body. Nerve cells are generally made up of three parts:
Neurotransmitters are located in a part of the neuron called the axon terminal. They’re stored within thin-walled sacs called synaptic vesicles. Each vesicle can contain thousands of neurotransmitter molecules. As a message or signal travels along a nerve cell, the electrical charge of the signal causes the vesicles of neurotransmitters to fuse with the nerve cell membrane at the very edge of the cell. The neurotransmitters, which now carry the message, are then released from the axon terminal into a fluid-filled space that’s between one nerve cell and the next target cell (another nerve cell, muscle cell or gland). In this space, called the synaptic junction, the neurotransmitters carry the message across less than 40 nanometers (nm) wide (by comparison, the width of a human hair is about 75,000 nm). Each type of neurotransmitter lands on and binds to a specific receptor on the target cell (like a key that can only fit and work in its partner lock). After binding, the neurotransmitter then triggers a change or action in the target cell, like an electrical signal in another nerve cell, a muscle contraction or the release of hormones from a cell in a gland. What action or change do neurotransmitters transmit to the target cell?Neurotransmitters transmit one of three possible actions in their messages, depending on the specific neurotransmitter.
What happens to neurotransmitters after they deliver their message?After neurotransmitters deliver their message, the molecules must be cleared from the synaptic cleft (the space between the nerve cell and the next target cell). They do this in one of three ways. Neurotransmitters:
How many different types of neurotransmitters are there?Scientists know of at least 100 neurotransmitters and suspect there are many others that have yet to be discovered. They can be grouped into types based on their chemical nature. Some of the better-known categories and neurotransmitter examples and their functions include the following: Amino acids neurotransmittersThese neurotransmitters are involved in most functions of your nervous system.
Monoamines neurotransmittersThese neurotransmitters play a lot of different roles in your nervous system and especially in your brain. Monoamines neurotransmitters regulate consciousness, cognition, attention and emotion. Many disorders of your nervous system involve abnormalities of monoamine neurotransmitters, and many drugs that people commonly take affect these neurotransmitters.
Peptide neurotransmittersPeptides are polymers or chains of amino acids.
AcetylcholineThis excitatory neurotransmitter does a number of functions in your central nervous system (CNS [brain and spinal cord]) and in your peripheral nervous system (nerves that branch from the CNS). Acetylcholine is released by most neurons in your autonomic nervous system regulating heart rate, blood pressure and gut motility. Acetylcholine plays a role in muscle contractions, memory, motivation, sexual desire, sleep and learning. Imbalances in acetylcholine levels are linked with health issues, including Alzheimer’s disease, seizures and muscle spasms. Why would a neurotransmitter not work as it should?Several things can go haywire and lead to neurotransmitters not working as they should. In general, some of these problems include:
Problems with other parts of nerves, existing diseases or medications you may be taking can affect neurotransmitters. Also, when neurotransmitters don’t function as they should, disease can happen. For example:
How do medications affect the action of neurotransmitters?Scientists recognized the value and the role of neurotransmitters in your nervous system and the importance of developing medications that could influence these chemical messengers to treat many health conditions. Many medications, especially those that treat diseases of your brain, work in many ways to affect neurotransmitters. Medications can block the enzyme that breaks down a neurotransmitter so that more of it reaches nerve receptors.
Medications can block the neurotransmitter from being received at its receptor site.
Medications can block the release of a neurotransmitter from a nerve cell.
A note from Cleveland Clinic Neurotransmitters play a role in nearly every function in your body. More specifically, neurotransmitters are the chemical communicators that carry a nerve’s message from one nerve cell to the next cell. Without neurotransmitters, your body can’t function. Too high of a level or too low of a level of specific neurotransmitters results in specific health problems. Medications work by increasing or decreasing the amount of or the action of neurotransmitters.
Last reviewed by a Cleveland Clinic medical professional on 03/14/2022. References
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