Serotonin And Antidepressant Action
Undoubtedly, a major reason for the continuing interest in serotonin and depression is the fact that SSRIs are useful antidepressant drugs for some patients. Elegant basic studies have revealed intriguing molecular and cellular consequences of repeated SSRI administration in animals, for example increases in hippocampal cell proliferation and enhanced expression of neuroplasticity related proteins such as brain derived neurotrophic factor . However, linking such changes to resolution of the clinical depressive syndrome is challenging. More pertinent in this respect are neuropsychological studies which show that, in both healthy participants and depressed patients, administration of SSRIs leads to positive shifts in the way the brain appraises emotionally-valenced information. This effect occurs very early in treatment, prior to clinical antidepressant effects, and appears to be mediated via serotonergic innervation to limbic circuitry, particularly the amygdala .
Serotonin And Vascular Maintenance
The vast majority of serotonin is secreted by the enterochromaffin cells of GI tract to control the movement of intestine . Platelets themselves cannot synthesize serotonin, due to a lack of enzymes responsible for serotonin synthesis. Instead, circulating platelets actively take up the serotonin released into the blood from the tissues . The reabsorbed serotonin in the blood can play important roles in vascular biology, including platelet activation, hemostasis and vascular endothelial cell and smooth muscle cell proliferation.
Under normal condition, platelets are kept balanced between quiescence and activation. Through binding onto the surface of platelets and conjugation to the adhesion and procoagulant proteins, serotonin can stimulate the activation of platelets . Another study also shows that platelet activation is mediated by the covalent cross-linkage of serotonin with small G proteins and the activation of G protein-dependent downstream signaling pathways .
Spend More Time In The Sun
One of the main root causes of seasonal depression, or seasonal affective disorder , is the overproduction of melatonin. Remember, your body produces melatonin from serotonin. Your pineal gland in your brain in response to darkness.
As it gets darker earlier, your body signals its time to release melatonin into your bloodstream.10
With longer periods of darkness in the winter months, your body uses more serotonin to make melatonin. This is why you may feel more depressed in the winter than in the summer. Spending 10 to 15 minutes outside every day, especially when the sun is shining, has been shown to increase serotonin levels.11
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Where Does Serotonin Come From
Serotonin is produced in the body’s nerve cells to transport signals between them. It is transported through the bloodstream via platelets and can be found all through the central nervous system. The highest levels of serotonin are located in the digestive system.Serotonin is produced from an essential amino acid – Tryptophan. Deficiencies of this amino acid are directly linked to low serotonin levels and the negative symptoms it causes. Tryptophan should be taken in regularly and is dependent on a person’s diet. You can ensure you are taking in Tryptophan by eating red meats, poultry, eggs, tofu, cheeses, and nuts.
Effects Of Stress And Social Interaction On Brain Serotonergic Activity
The development of dominance-based social hierarchy is common among teleost fish. The social rank of individual fish within a hierarchy is usually determined by the outcome of dyadic aggressive encounters . These aggressive interactions consist of behaviors such as displays, charging, nipping, and chasing. Fish losing aggressive interactions becoming subordinate will suppress further aggression and retreat from the dominant individual . The winner, the dominant individual, on the other hand, remains highly active and aggressive. Behavioral effects of social defeat include appetite inhibition , reduced aggression , and decreased reproductive behavior .
Social subordination results in drastic behavioral effects in fish. The subordinate fish displays a general behavioral inhibition, including suppression of aggressive behavior, feeding, and locomotion . A chronic activation of the brain serotonergic system seems to play an important role in mediating these behavioral effects .
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A Happy Chemical: Serotonin And Mood
Serotonin is sometimes known as the happy chemical, because it appears to play an important role in regulating mood, and low levels of serotonin in the brain have been associated with depression.
While theres a link between low levels of serotonin and depression, its not clear whether low serotonin levels cause depression or whether depression causes a drop in serotonin levels.
As a neurotransmitter, serotonin sends messages between nerve cells in the brain. That makes serotonin an important molecule for influencing mental health and brain function.
Dangers Of Too Much Serotonin
Always ask your doctor before taking any medication or supplement to increase low serotonin. Certain medications and supplements can raise serotonin levels too much, which can lead to serotonin syndrome.
The symptoms of serotonin syndrome range from unpleasant to life-threatening and can include sudden swings in blood pressure, seizures, and loss of consciousness.
Serious cases of serotonin syndrome can be fatal if left untreated. If you or a loved one is showing symptoms of serotonin syndrome, or go to the nearest emergency room.
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The Effect Of Drugs On Serotonin
When a person uses a drug, he will experience several side effects. These effects include both physical and psychological changes, and can be either short-term or long-lasting. Some of the most pronounced effects of drug use, though, appear in the brain. All drugs interact with the brain in some way, and most affect how it communicates with other parts of the body.
Specifically, many drugs interact with the brains neurotransmitters, which serve as the messengers for the brains communication system. One type of neurotransmitter is called serotonin, which functions in the brain as a conveyer of feelings of well-being and contentment. Since some types of drugs interact with serotonin, a persons sense of happiness and well-being can be affected when he takes these kinds of drugs.
How Does Tms Help Serotonin And Dopamine Levels
TMS uses an electromagnetic field to provide an electrical impulse to neurons, including those responsible for releasing neurotransmitters like serotonin and dopamine.
You might think that this sounds similar to how antidepressants work, but antidepressants actually focus on the chemical parts in the brain. TMS, on the other hand, specifically targets the electrical activity within neurons.
TMS is capable of actively targeting and engaging neurotransmitters in your brainprimarily in the prefrontal cortexthat often cannot function normally when you are depressed. For instance, when you are depressed, you are often more prone to thinking negatively about yourself and find it more difficult to silence those negative self-reflections to focus on something else.
Dopamine is one of the neurotransmitters in the prefrontal cortex region of the brain that TMS can help regulate. Several research studies have demonstrated that TMS normalizes your serotonin and dopamine levels and activity, thereby improving depressive symptoms, including negative ruminations and poor concentration.
Not only does it enhance the release of serotonin and dopamine, but TMS also helps to strengthen the synaptic plasticity of your brain. Remember that synaptic plasticity refers to how well neurons communicate with one another. The communication between certain neurons is often not fully effective in the brains of individuals with depression, including the prefrontal cortex.
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Why Does The Human Body Use Serotonin
As a neurotransmitter, serotonin regulates the intensity of the synaptic signal. 5-HT plays various other important roles affecting both bodily and psychological functioning.
Heres a partial list of how serotonin works in the body:
- Adjustment of mood, appetite, digestion, social behavior, libido, sleep and memory
- A supporting role in breast milk production
- Used to metabolize bone
- Geographic Location
- Other factors ..
In some cases, low levels of serotonin are associated with depression. It is not yet clear whether depression causes a decrease in serotonin levels or if depression is already caused by low serotonin levels.
In any case, low levels of 5-HT are a very common occurrence among individuals with depression.
Because 5-HT cannot be directly supplemented, a study was conducted with 5-HTP as a way to increase serotonin levels in the brain. The Natural Medicines Database has evaluated 5-HTP as a potentially effective dietary supplement in depression. Some studies have suggested that the use of 5-HTP may be similar to some common antidepressant medications.
Selective Serotonin Reuptake Inhibitors
SSRIs are selective serotonin reuptake inhibitors, and are the most commonly prescribed antidepressants, though they are also used for anxiety disorders. They ease the symptoms of moderate to severe depression and are generally considered safe, causing fewer side effects than other antidepressants.
They work by increasing serotonin levels in the brain. SSRIs prevent the reabsorption of serotonin into neurons, making more available in the brain, improving the transmission of messages between neurons .
The Food and Drug Administration has approved the following SSRIs to treat depression:
- some herbs, such as St. John’s Wort
- some over-the-counter cough and cold medications
- cocaine, LSD, ecstasy, and amphetamines
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What Is A Neurotransmitter
To understand chemical imbalances in the brain, its important first to understand a little bit of neuroscience. Essentially, our brain communicates with our body through chemical substances called neurotransmitters, which are capable of sending internal messages to various cells and muscles. These messages are responsible for processes that we might not think twice about, such as breathing, as well as more complex tasks, such as moods.
Neurotransmitters are passed through our brain via passageways called synapses. The synapses are responsible for passing chemical messages, such as neurotransmitters, between neurons.
Neurons are specialized cells that process information. There are many different kinds of neurons in our brain, ranging from neurons that control our motor functions to those that interpret the data we receive from our five senses.
Some neurons in our brain communicate well with one another via their synapses. Other neurons have trouble having productive conversations with each other. This variance in the neurons ability to communicate is called synaptic plasticity. Synaptic plasticity can change over time, becoming either better or worse.
What Are Serotonin and Dopamine?
Serotonin is one type of neurotransmitter. This neurotransmitter plays a role in digestion, sexual function, bone density, blood clotting, and emotional regulation. When you have the right amount of serotonin inside your body, it is easier to have stable moods and a sense of well-being.
How Does Serotonin Help With Memory Improvement
There are many memory improvement benefits with having normal or slightly elevated serotonin levels in the brain. One is that Serotonin is the precursor to the hormone, Melatonin. Melatonin is made in the pineal gland and is released at night to signal to your body that it is time to go to sleep. Getting enough sleep for your brain to fully recover is essential when it comes to moving information from short term memory to long term memory.
In a study done by John Hopkins, they state the following three main points about Serotonin and those with early-onset signs of dementia or memory issues.
- Lower serotonin transporter binding is observed in mild cognitive impairment versus controls in cortical, limbic, sensory and motor regions.
- Reductions in the serotonin transporter were more statistically robust than cerebral atrophy in mild cognitive impairment compared to controls.
- Lower serotonin transporter binding was associated with worse performance in verbal and visual-spatial memory in mild cognitive impairment.
Now this doesnt necessarily mean that having low levels of Serotonin causes dementia or Alzheimers but it does say that those with cognitive issues showed that they had low levels of Serotonin compared to control groups of healthy individuals.
More research still needs to be done to have a definitive answer as to whether or not serotonin alone can directly benefit healthy individuals brains when it comes to memory improvement.
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Mental Health And Emotions
Serotonin is responsible for natural mood regulation, controlling things like focus, happiness, and anxieties. The lack of serotonin is severe, with studies suggesting that low levels may cause depression, anxiety, insomnia, suicidal behavior, obsessive-compulsive disorder, and other behavioral disorders.
Serotonin Release And Reuptake
When neurons communicate with each other, the presynaptic neuron releases neurotransmitters into the synaptic space, which are picked up by receptors on the postsynaptic neuron.
In the case of circuits for the neurotransmitter serotonin, neurons use this neurotransmitter to communicate. One neuron releases serotonin into space and the other picks it up, understanding that it must be activated.
What happens is that not all neurotransmitters are received and sometimes they remain floating in the intersynaptic space. There are pumps that are responsible for cleaning this excess neurotransmitter and returning it to the presynaptic neuron.
In depression and other disorders, it is hypothesized that there is very little serotonin in this space so that serotonin-starved postsynaptic neurons create many receptors to receive neurotransmitters but are not activated and do not release anything, as in a state of hibernation.
SSRIs block reuptake pumps and allow more and more serotonin to accumulate in space.
Post-synaptic neurons, as they perceive that the concentration of serotonin in space is higher and there is more neurotransmitter available, begin to decrease the number of receptors because they no longer believe they need so many.
The neuron relaxes its strict norm of not releasing anything and begins to let go of serotonin and activate the rest of the neurons in the circuit.
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How Are Serotonin And Dopamine Linked To Depression
It is common for people with depression to have low levels of dopamine. If you are depressed, it is often difficult to motivate yourself to do things, be it routine tasks like going to work or social activities like spending time with your family. You probably also have trouble experiencing pleasure even when doing activities you used to love.
The research surrounding serotonin and depression is more complicated. In the 1950s, the prevailing theory was that low levels of serotonin led to depression. This hypothesis came about initially because iproniazid, a drug originally designed to treat tuberculosis, was found to greatly improve patients moods, to the point of near-euphoria in many. Scientists speculated that this was because iproniazid increased the presence of neurotransmitters such as serotonin. This theory was lent further weight over the next few decades by other evidence, such as how autopsies of suicide victims had less serotonin in their brains than people who died by other means.
Serotonin Endocrinology And Metabolism
The functions of serotonin in the endocrine system and metabolism range from the central control of energy balance and central modulation of the hypothalamic-pituitary-adrenal axis to the direct regulation of mammary gland development . Several lines of evidence suggest an important role for hypothalamic 5-HT2C receptors in regulating energy balance and modulating glucose homeostasis . In particular, hypothalamic 5-HT2C and 5-HT1B receptors act by modulating melanocortin pathways, and serotonin release into the hypothalamus stimulates sympathetic nerves that innervate brown adipose tissue . Because of these mechanisms, 5-HT2C receptor agonists may be useful for treating obesity and diabetes . Serotonin also plays a role in setting overall metabolic rate and temperature control. Serotonin-deficient mice show a rapid hypothermic response when placed in a cold environment , a response that may be mediated by hypothalamic 5-HT1A and 5-HT7 receptors . Serotonin regulates the HPA axis at multiple levels and thus has complex effects on the overall stress response.
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How Does Serotonin Work
Serotonin is both a neurotransmitter and a hormone. When it acts as a neurotransmitter, serotonin will hop from neuron to neuron to send messages. These messages alert and activate certain areas of the brain and nervous system, resulting in physical outcomes.Serotonin also acts as a hormone. This means it is released into the bloodstream, specifically blood platelets and the gut. It will then move through the bloodstream and digestive system to communicate signals and stimulate physical reactions.The cells of the body contain serotonin receptors, which are necessary to receive the messages that serotonin carries. Faulty receptors may lead to many of the same symptoms as serotonin deficiencies.Serotonin is produced inside your body, mainly in the digestive tract. It is released during events that impact the systems it affects. For example, when you laugh serotonin is released to stimulate happiness. When you eat something bad, serotonin is released to stimulate nausea and remove it from the body.
Computational Approaches To Serotonin Function
Computational neuroscience offers a framework that allows the role of specific neurotransmitters to be dissected from within a complex, interconnected and dynamic system such as the brain. The paradigmatic example of a computational approach to understanding the function of a central neurotransmitter is the finding that activity in a subset of dopaminergic neurons, projecting from the ventral tegmentum throughout the brain, sharply increases when an unexpected reward occurs . Computational accounts suggest that these dopamine neurons contain information about the reward prediction error, which is calculated simply as the difference between the reward the animal expected to receive and what it actually received . This provides a compelling quantitative account of the role of dopaminergic neurons in updating beliefs about the environment.
The role of serotonin in cognition has not, to date, been characterized as successfully as the dopaminergic reward prediction error signal. This may in part be due to the technical challenges of identifying serotonergic neurons electrophysiologically or the low concentrations of serotonin compared to dopamine in the central nervous system, problems which may be more readily circumvented in the future by advances in optogenetics . Whatever the cause, no existing computational account of serotonergic function commands the empirical support enjoyed by the dopaminergic model.
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Problems With The Bodys Internal Clock
Serotonin helps regulate the bodys circadian rhythm, which is its internal clock. Though its common for people to have difficulties getting up in the morning or occasionally forget meals, dysregulation in the internal clock can cause serious sleep, appetite, and other issues. A person who never sleeps according to a regular schedule, who has difficulty maintaining a consistent pattern of hunger and eating, or who feels chronically tired or hyper could have a problem with their circadian rhythm. This may be due to low serotonin.