Neurotransmitters Associated With Depression
Depression has been linked with reduced action of serotonin, norepinephrine and dopamine in the brain :
Serotonin has many functions, one of which seems to be the production of a feeling of contentedness, connectedness and peacefulness. When levels of serotonin are reduced, people tend to feel more anxious, stressed, irritable, aggressive, impulsive and depressed. SSRI antidepressants seem to have their effect by increasing the levels of serotonin in the brain available for signaling. There are various types of serotonin receptors in the brain, and their functions are not completely understood. Increased levels of serotonin 2A receptor in the brain have been associated with having Depression as well as with experiencing more frequent depressive thoughts this may reflect the brain’s attempt to compensate for overall low levels of serotonin, but another hypothesis is that serotonin 2A receptors might actually be involved in the actual process of Depression, because blocking these receptors with antidepressants like Mirtazepine is a way to treat Depression. Stimulating serotonin 1A post-synaptic receptors is also thought to be a way to treat Depression.
Norepinephrine seems to produce, among other things, a feeling of excitement, interest, initiative, power and dominance. Low levels of this neurotransmitter can lead to states of low energy, loss of interest or motivation, and feelings of defeat and low self-esteem.
Is There Chemical Imbalance In The Brain That Causes Depression
Depression is also a multi-faceted condition, but having an awareness of the brain chemistry component can be useful for medical and mental health professionals, researchers, and many people who have depression. Heres an overview of what is known about how chemical imbalances in the brain may influence depression.
Can The Brain Repair Itself After Depression
A depressed persons brain does not function normally, but it can recover, according to a study published in the August 11 issue of Neurology, the American Academy of Neurologys scientific journal. Researchers measured the brains responsiveness using magnetic stimulation over the brain and targeted muscle movement.
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Disorders Associated With Neurotransmitters
When there is an imbalance in neurochemicals, it can cause problems. For example, sometimes other neurons may not produce enough of a neurotransmitter, or the neurotransmitter may be reabsorbed too quickly.
Occasionally the body may release neurotransmitters too fast or also release too much. These problems can lead to a variety of adverse effects.
Alzheimers, epilepsy, and Parkinsons disease are all associated with deficits in critical neurotransmitters.
Researchers also recognize that neurotransmitters can have an impact on mental health. Because of this, many treatment options for posttraumatic stress disorder, depression, anxiety, and more are developed with this in mind.
Selective serotonin reuptake inhibitors are some of the most popular antidepressant medications, and SSRIs work by increasing serotonin levels in the brain.
Another type called tricyclic antidepressants works by increasing serotonin and norepinephrine but blocking acetylcholine at the same time. Both options for depression work best when combined with therapy and other treatment options.
Neuroscience shows us that inadequate dopamine may also be involved with some health disorders and diseases, including schizophrenia, ADHD, and addiction. Not only that, but too little dopamine may also cause gastrointestinal and muscular problems.
What Causes Depression In The Brain
One of the most difficult aspects of understanding depression is pinpointing its root causes, as they vary from person to person. Sometimes, the reason is clear, such as witnessing or living through a traumatic event. Other times, the reason for depression is subtle and hidden under layers of suppressed memories. There are even times when were depressed for no clear reason. To help us understand why depression can manifest itself in so many different ways, researchers study the brain. Since our brains control, manage and balance our emotions, they are the key to understanding how and why we develop depression in the first place.
A Harvard Medical School special report, Understanding Depression explains the condition like this: Certain areas of the brain help regulate mood. Researchers believe thatmore important than levels of specific brain chemicalsnerve cell connections, nerve cell growth, and the functioning of nerve circuits have a major impact on depression.
Many of us blame our brain chemistry for depression or anxiety. But research like the report above indicates that the brains role in depression is much more complex than simply regulating emotions. Instead, the difference between a person who struggles with depression and a person who does not may have more to do with how the different parts of our brain work together.
Lets explore more about neurotransmitters and their role in the brain.
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The Role Of Key Neurotransmitters
The three neurotransmitters implicated in depression are:
There are other neurotransmitters that can send messages in the brain, including glutamate, GABA, and acetylcholine. Researchers are still learning about the role these brain chemicals play in depression and other conditions, such as Alzheimer’s and fibromyalgia.
The Potential Of Glutamate Modulators
The glutamatergic system is complex and ubiquitous throughout the brain, hence the fear that intervening with pharmaceutical agents will cause harm as well as good. Despite these concerns, emerging evidence shows that a number of different agents acting on the NMDA and AMPAR receptors, may have antidepressant properties, including antagonists, partial agonists, and allosteric modulators. The seemingly contradictory modes of action of some of the drugs are due to factors such as differences in location of receptor target and dose used. With further research, agents acting on these receptors may emerge which are both efficacious and safe for the treatment of depression.
Educational financial support for this session was provided by Allergan plc
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Which Neurotransmitter At Low Levels Is Associated With Depression
Which neurotransmitter at low levels is associated with depression? Low levels of norepinephrine, serotonin, and dopamine are also associated with various aspects of depression. When our bodies produce low levels of these neurotransmitters, our odds of experiencing symptoms of depression can increase.
What is the neurotransmitter that has lower levels in people with major depression? Kinds of neurotransmitters.
Serotonin helps regulate sleep, appetite, and mood and inhibits pain. Research supports the idea that some depressed people have reduced serotonin transmission. Low levels of a serotonin byproduct have been linked to a higher risk for suicide.
What 3 neurotransmitters are linked to depression? A relationship appears to exist between the 3 main monoamine neurotransmitters in the brain and specific symptoms of major depressive disorder.
Which neurotransmitter is involved with regulating mood and in low levels can cause depression? Serotonin is an inhibitory neurotransmitter. It helps regulate mood, appetite, blood clotting, sleep, and the bodys circadian rhythm. Serotonin plays a role in depression and anxiety.
Key Neurotransmitters And Depression
Norepinephrine
- Norepinephrine is a neurotransmitter and a hormone that sends flight or fight messages throughout different cells in our brains. It also plays an important role in how our brains and bodies process and interpret the hormone adrenaline. Located in our sympathetic nervous system, which controls our bodys rapid, involuntary responses to dangerous or stressful situations, norepinephrine is also known for constricting blood vessels and raising blood pressure.
Serotonin
- Serotonin helps regulate our mood. It also sends messages throughout the brain that let us know when we need to eat, digest, and sleep. In addition to that, serotonin sends signals that reduce pain, regulate anxiety, stimulate nausea, heal wounds, and block pain, too. Despite what most of us might think, most of the serotonin in our bodies is in the gut, not the brain. Regardless of that, serotonin plays a central role in relaying messages about our emotional state.
Dopamine
- Known as a feel good chemical, dopamine sends positive signals related to reward. When dopamine transmits a message between our neurons, our brains receive positive reinforcement and were encouraged to perform that dopamine-triggering activity again. Because dopamine sends pleasurable messages between nerve cells, this neurotransmitter helps motivate us and stimulates our interest in certain activities, people, and places.
Other neurotransmitters that affect our emotions and mood include:
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What Is The Biochemical Basis Of Depression
Steven Gans, MD is board-certified in psychiatry and is an active supervisor, teacher, and mentor at Massachusetts General Hospital.
There are several theories about what causes depression. The condition most likely results from a complex interplay of individual factors, but one of the most widely accepted explanations cites abnormal brain chemistry.
Sometimes, people with depression relate the condition back to a specific factor, such as a traumatic event in their life. However, it’s not uncommon for people who are depressed to be confused about the cause. They may even feel as though they don’t have “a reason” to be depressed.
In these cases, learning about the theories of what causes depression can be helpful. Here’s an overview of what is known about how chemical imbalances in the brain may influence depression.
Neurotransmitter Testing Has No Scientific Validity
A comprehensive analysis of neurotransmitter testing concluded that there is no connection between neurotransmitters found in the urine and those in the brain.
Another study on the viability of commercial neurotransmitter testing found that these tests have no scientific foundation, and that there was an abundance of evidence refuting their validity.
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Loss Of Ahi1 Impairs Neurotransmitter Release And Causes Depressive Behaviors In Mice
- Liyan Ren ,
Contributed equally to this work with: Liyan Ren, Xuanchen Qian
Affiliation Department of Neurology and Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, the Second Affiliated Hospital of Soochow University, Suzhou City, Jiangsu Province, China
- Xuanchen Qian ,
Contributed equally to this work with: Liyan Ren, Xuanchen Qian
Affiliation Department of Neurology and Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, the Second Affiliated Hospital of Soochow University, Suzhou City, Jiangsu Province, China
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Affiliation Department of Neurology and Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, the Second Affiliated Hospital of Soochow University, Suzhou City, Jiangsu Province, China
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Affiliation The Institute for Fetology, the First Affiliated Hospital of Soochow University, Suzhou City, Jiangsu Province, China
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Affiliation The Institute of Neuroscience, Soochow University, Suzhou City, Jiangsu Province, China
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Affiliation Department of Neurology, Suzhou Kowloon Hospital, Suzhou City, Jiangsu Province, China
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* E-mail:
Affiliations Department of Neurology and Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, the Second Affiliated Hospital of Soochow University, Suzhou City, Jiangsu Province, China, The Institute of Neuroscience, Soochow University, Suzhou City, Jiangsu Province, China
Neurotransmitter Testing: Take The Next Step
The first neurotransmitter was discovered less than 100 years ago.
Our understanding of how they work, of the links between them and mental health disorders, and of reliable ways to test them are still in the early stages.
Someday, maybe a lab test will be able to accurately tell you whats wrong with your brain chemistry and how to fix it.
But that day is not here yet.
Until then, the best option is to use your signs and symptoms as a guide.
Use our signs and symptoms lists or take one of the professionally developed quizzes we recommend to draw your own conclusions.
Then, use this information to optimize your neurotransmitter levels with appropriate lifestyle measures and by working with a health care professional, if necessary.
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Reasons To Be Skeptical Of Laboratory Neurotransmitter Testing
Scientists have found over one hundred neurotransmitters and more will certainly be discovered.
Its estimated that most of us have suboptimal neurotransmitter levels, with our unhealthy modern lifestyle largely to blame.
Chronic stress, poor diet, environmental toxins, drugs , alcohol, nicotine, and caffeine can cause neurotransmitter depletion.
Every laboratory offers a different menu of tests, but typically a neurotransmitter testing panel will encompass some or all of these major neurotransmitters:
- serotonin
- memory loss
- mood swings
As you might expect, the biggest proponents of neurotransmitter testing are the laboratories that sell these tests and the doctors who use them .
These companies often recommend and sell supplements as well.
There is plenty of potential for conflict of interest.
” There is no scientifically validated way to test neurotransmitter levels through lab testing. The best way is to assess your symptoms.
One neurotransmitter testing company, NeuroScience, Inc., was fined over $6 million for violating laboratory testing requirements.
The company founder admitted his company intentionally manipulated neurotransmitter test results and then recommended and provided supplements based on these bogus test results.
In a separate lawsuit, NeuroScience was also found guilty of Medicare fraud.
One neurotransmitter lab website has the catchy slogan test, dont guess.
But are these tests any better than guessing?
What Is A Neurotransmitter
Neurotransmitters exist as the bodys chemical messengers that communicate with each other and with target tissues through synaptic transmission or neurotransmission.
Overall, over 40 neurotransmitters exist within the human central nervous system , each having a specific and vital function for human behavior.
However, scientists still dont know exactly how many neurotransmitters in total are in the human brain.
Neurotransmitters are synthesized and released from the nerve ending into the synaptic cleft, and then they bind to receptor proteins in the cellular membrane of the target tissue.
In addition, small-molecule transmitters do most of the work and include GABA, acetylcholine, dopamine, and more.
According to neuroscience, there are three different types of neurotransmitters identified depending on the action of the target cells.
How the neurotransmitter affects the target cell determines whether it is a modulating, excitatory, or inhibitory neurotransmitter 30156-4″ rel=”nofollow”> 1).
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Dopamine And Anxiety: What Does Dopamine Have To Do With Fear
Research shows that depression has links with Dopamine, but the latest scientific studies suggest that it may play a key role in anxiety-related behaviours. Typically dopamine is associated with pleasure addictive behaviours. However, sometimes fear has relations with dopamine levels. Fear and phobia are a part of many anxiety disorders such as phobia, social anxiety, generalised anxiety, PTSD. While fear contributes to the dopamine level, it also contributes to anxiety-like behaviour.
Genes’ Effect On Mood And Depression
Every part of your body, including your brain, is controlled by genes. Genes make proteins that are involved in biological processes. Throughout life, different genes turn on and off, so that in the best case they make the right proteins at the right time. But if the genes get it wrong, they can alter your biology in a way that results in your mood becoming unstable. In a person who is genetically vulnerable to depression, any stress can then push this system off balance.
Mood is affected by dozens of genes, and as our genetic endowments differ, so do our depressions. The hope is that as researchers pinpoint the genes involved in mood disorders and better understand their functions, depression treatment can become more individualized and more successful. Patients would receive the best medication for their type of depression.
Another goal of gene research, of course, is to understand how, exactly, biology makes certain people vulnerable to depression. For example, several genes influence the stress response, leaving us more or less likely to become depressed in response to trouble.
The evidence for other types of depression is more subtle, but it is real. A person who has a first-degree relative who suffered major depression has an increase in risk for the condition of 1.5% to 3% over normal.
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Regions That Affect Mood
Increasingly sophisticated forms of brain imaging such as positron emission tomography , single-photon emission computed tomography , and functional magnetic resonance imaging permit a much closer look at the working brain than was possible in the past. An fMRI scan, for example, can track changes that take place when a region of the brain responds during various tasks. A PET or SPECT scan can map the brain by measuring the distribution and density of neurotransmitter receptors in certain areas.
Use of this technology has led to a better understanding of which brain regions regulate mood and how other functions, such as memory, may be affected by depression. Areas that play a significant role in depression are the amygdala, the thalamus, and the hippocampus .
Research shows that the hippocampus is smaller in some depressed people. For example, in one fMRI study published in The Journal of Neuroscience, investigators studied 24 women who had a history of depression. On average, the hippocampus was 9% to 13% smaller in depressed women compared with those who were not depressed. The more bouts of depression a woman had, the smaller the hippocampus. Stress, which plays a role in depression, may be a key factor here, since experts believe stress can suppress the production of new neurons in the hippocampus.
Glutamatergic Hypothesis Of Depression
Glutamatergic neurons constitute approximately 80% of the synapses in the neocortex . Glutamate is released at synapses throughout the brain, and exerts changes in postsynaptic excitability and neuroplasticity . It activates various downstream pathways of nuclear genes by binding to a variety of membrane-bound receptors present on the postsynaptic membrane, which regulate secondary messenger systems. -Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid , N-methyl-D-aspartate , and kainate are the fast-acting ionotropic receptors that get activated by glutamate binding . Glutamate also binds to G-protein-coupled receptors, known as metabotropic glutamate receptors, which mediate various cellular processes and slow-acting changes through secondary messengers such as cyclic adenosine monophosphate , cyclic guanosine monophosphate and phosphatidylinositol . AMPA and kainate receptors help in the conduction of action potential primarily through the flux of Na+ ions, while NMDAR is distinguished by its more permeability to Ca2+ ions. NMDA receptor signaling promotes various responses such as excitation, neurotrophic function, and can even activate cell death pathways. Abnormal activity of NMDA receptor imparts harmful effects on neurons . Overexcitation of NMDAR by excessive glutamate release or impaired synaptic clearance leads to the death of neurons by excitotoxicity .
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