Because of our somewhat limited understanding of the brain and its processes, it is not known for certain what causes depression; however, there are many theories. Many of these hypotheses are based upon synaptic transmission, the concentration of neurotransmitters (mainly serotonin and norepinephrine), and their transporters in the brain. Neurotransmitters are chemicals that transmit chemical signals from one neuron to the next. In a normal functioning system, neurotransmitters are synthesized in neurons from molecules called monoamines, and their release into the synaptic cleft is based on Ca+2. The neurotransmitters cross the synaptic cleft and will bind to G-protein coupled receptors on the membrane of the neighboring neuron, causing regulation of biological processes that have both short- and long-term effects on the brain. If any of the preceding steps are affected, depression may result. …show more content…
In studies that examine serotonin and norepinephrine (NE) it is observed that the concentrations of these chemicals are lower than normal in depressive states. This may point to a deficiency in the concentration of monoamines, which are the chemical precursors to neurotransmitters. Enzymes that control the synthesis and breakdown of neurotransmitters may also play a role in depression. For example, the inhibition of tyrosine hydroxylase, which synthesizes NE, leads to decreased concentrations of NE in the synapse. Furthermore, decreased levels of monoamines and enzyme deficiencies, defects in neurotransmitter receptors on post-synaptic membranes may lead to depression. The signal-cascade pathway that occurs after a neurotransmitter binds to its receptor may be affected at the G-proteins on the surface of the neuron, the cAMP pathway, and protein
If you have been diagnosed with depression, you most likely will be told it is due to a deficiency of serotonin. Serotonin is regarded by many people as the basic neurotransmitter, or chemical hormone, that regulates mood. It plays the central role in the regulation of human mood and temperament. Serotonin is an inhibitory neurotransmitter which works with the excitatory sympathetic systems, like adrenaline and dopamine, in the central nervous system. Most widely researched are the effects on the central nervous system. An oversupply of serotonin can occur, though it is not as common, and it can cause vivid hallucinations, vascular disorders, and psychotic disorders. If you have a sustained decrease in serotonin, the following will occur: increase in anxiety, loss of interest, and lack of concentration. Having a decrease or imbalance in the body sounds somewhat alarming, but there are ways to cope and restore normal balances regarding serotonin.
In accordance with biological views, minimal operation of neurotransmitters called serotonin and norepinephrine, are agents of depression. Hormonal elements may also be involved, and the biological issues mentioned could be combined with genetic factors. Efficacious biological management for unipolar depression are electroconvulsive therapy (ECI) and antidepressant drugs such as MAO inhibitors, tricyclics, and second generation antidepressants (Comer, 2005).
Serotonin syndrome is a drug-induced syndrome that results in mental, autonomic and neuromuscular changes. A range of toxic symptoms including clonus, hyperreflexia, tremor, agitation, confusion and shivering are results of the increased serotonin concentrations in the central nervous system (Hall and Buckley, 2003). Serotonin (5-hydroxytryptamine, 5-HT) is a neurotransmitter produced from the decarboxylation and hydroxylation of tryptophan. Serotonin is stored within the vesicles and released into the synaptic cleft when stimulated (Volpi-Abadie et al., 2013). As serotonin influences on mood, sleep, vomiting and pain perception, the serotonin levels are tightly regulated by the reuptake mechanisms, degradation by monoamine oxidase type A and feedback loop (Thanacoody,
Clinical and preclinical trials point to a disruption in central nervous system serotonin activity as an important influence. Norepinephrine, dopamine, glutamate, and brain-derived neurotrophic factor are other neurotransmitters included. However, medications that cause only an acute rise in neurotransmitter availability, such as cocaine or amphetamines, do not have the effectiveness over time that antidepressants do.
Neurotransmitters are chemicals made by neurons and used by them to transmit signals to the other neurons or non-neuronal cells (e.g., skeletal muscle; myocardium, pineal glandular cells) that they innervate. The neurotransmitters produce their effects by being released into synapses when their neuron of origin fires (i.e., becomes depolarized) and then attaching to receptors in the membrane of the post-synaptic cells. This causes changes in the fluxes of particular ions across that membrane, making cells more likely to become depolarized, if the neurotransmitter happens to be excitatory, or less likely if it is inhibitory.
Synaptic activity is vital for the passage of information throughout the nervous system, as it allows for electrical impulses to be passed from one neuron to another. Electrical impulses in the form of action potentials are passed through the axon of a neuron towards the axon terminal. This information is then passed across the synaptic cleft to receptors present on the postsynaptic membrane via the process of neurotransmission. Drugs can interrupt this specific process in a variety of ways such as through affecting the production, storage and release of neurotransmitters, the presynaptic and postsynaptic receptors as well as the reuptake and destruction of neurotransmitters (Carlson, 2014). Selective Serotonin Reuptake Inhibitors (SSRIs) and Monoamine Oxidase Inhibitors (MAOIs) are just two types of drugs which can affect different pathways in this process of neurotransmission. In doing so, the neurotransmitter serotonin is made more available within the central nervous system (CNS), a neurotransmitter believed to be central to the affective disorder of depression, which is caused by a deficiency of serotonin.
The synaptic gap or the synaptic cleft is where the axon is sending chemical substances to dendrite. Pre-synaptic neuron is transmitting neurotransmitter and post-synaptic neuron receives neurotransmitter. Neurotransmitter can affect or mental abilities and there are different types of them. Like; Acetylcholine (ACh), Dopamine, Serotonin, Norepinephrine, Gamma-aminobutyric acid (GABA), Glutamate. Acetylcholine helps work the muscles. And also, learning and memory. When the brain not producing ACh the way they should be; this is how Alzheimer’s disease develop. Dopamine plays the role of moods, motivation, learning, and movement. Malfunctions of this neurotransmitter is Parkinson’s disease and schizophrenia. Parkinson’s happens when the brain is undersupplying of dopamine and schizophrenia is overproducing. Serotonin have an impact on mood, appetite, regulate sleep, and arousal. When the brain is undersupply of serotonin, mental disease like, depression are developed. This is why in antidepressant, it helps raise the levels of serotonin. Norepinephine have the ability to regulate alertness and arousal. Similar to serotonin, depression occur when there is a low amount levels of norepinephine. GABA is a very major neurotransmitter, it controls and regulate sleep, relaxation and anxiety. Seizures, tremors, and insomnia involves when the brain is low with GABA. Glutamate have similar ability to the
According to Merriam-Webster Dictionary, a neurotransmitter is “a substance that transmits nerve impulses across a synapse” and a synapse is the “site of transmission of electric nerve impulses between two nerve cells or between a nerve cell and a gland or muscle cell” (2014). Neurotransmitters play a crucial role in the chemical balance of the human body and their changing levels are believed to be one of the primary reasons for depression and its manifestations. The issue can either be with the receptors being too sensitive or not sensitive enough or that not enough is being released (?).
The two types of neurotransmitters that affect our nervous system are inhibitory neurotransmitters and excitatory neurotransmitters. Inhibitory neurotransmitters decrease the activity of the nervous system while excitatory neurotransmitters excited the nervous system. Neurotransmitters can be involved in a variety of different activities in our bodies such as movement, pain perception, thinking, and emotion. The main purpose of neurotransmitters is to communicate among neurons by being released into the synapse and binding with a receptor site along the dendrites of nearby neurons. Since your grandfather's illness is concerned with excitatory neurotransmitters such as acetylcholine and dopamine, I will focus on those two.
These neurons can only be received onto certain sites, known as a receptor. Neurotransmitters can fit a number of different receptors, but receptor sites can only receive specific types of neurotransmitters (Biological Causes of Depression). At the receptor site of a neuron, the chemical message of the neurotransmitter may either change into electrical impulses and continue on its way through the next neuron, or may stay where it is (Biological Causes of Depression). Within this process, enzymes can help break down other neurotransmitters into smaller ones. If this systems fails to cooperate with each other, then the production of neurotransmitters, that are there to maintain a balance, can affect the mood of the person. Thus, resulting in behavioral differences from the common characteristics of the
These can be caused by a low production of serotonin in our brain or a lack of receptor sites from serotonin to bind to. There are many other ways these problems can become the issue, including the inability for the serotonin to reach these receptor sites or a shortage of the chemical used to make serotonin, Tryptophan. People with depression can take antidepressant drugs, such as SSRI or selective serotonin reuptake inhibitors which help regulate serotonin levels, in order to reduce the symptoms of depression. Serotonin is known as the “happy molecule”, because of its role that it plays in determining your mood. The major serotonin deficiency is depression or the loss of pleasure in normal things you used to enjoy. Other deficiencies in our levels of serotonin include anger, digestive disorders, feeling overwhelmed, insomnia, low self-esteem, and migraines just to name a few. The effects of serotonin are different in men and women in many ways. Women, for instance, are more likely to experience depression, anxiety, and other mood
The brain contains neurons which send electrical impulses and chemical signals to the brain as well as the rest of the nervous system. The chemical message delivered is called a neurotransmitter which then send messages between neurons. The problem occurs when this process does not work correctly. Nimh.nih.gov's article "The Working Brain" tells that "Communication between neurons can also be electrical, such as in areas of the brain that control movement. When electrical signals are abnormal, they can cause tremors or symptoms found in Parkinson's disease" ("Working"). The brain will decide when it wants the body to tremor or display another symptom of a disease which is completely out of the person's control. Three main neurotransmitters released from the brain are serotonin, dopamine and glutamate. Serotonin controls many functions including mood, hunger and a person's sleep schedule. Those diagnosed with depression usually are lacking in their serotonin levels. Dopamine mainly controls movement and focuses on the flow of information to the brain. Having too little amounts of dopamine can play a role in developing disorders such as schizophrenia and attention deficit disorder. Glutamate is the most common, having many important roles involving the brain and nervous system. Many mental disorders arise from having a problem with making or using glutamate. Autism, obsessive
An example of a monoamine is the chemical, serotonin. Serotonin is considered a indolamine neurotransmitters that affects and regulates a person’s mood and is also involved with sleep and dreaming as well as eating, arousal and pain. It also If a person has low levels of serotonin it could cause depression but drugs that are considered a serotonin and norepinephrine reuptake inhibitor, such as Prozac, can help to raise the levels of serotonin. About 80% of the human body’s serotonin is found in certain cells in the gut. While here, the serotonin helps to regulate intestinal movements. The remaining 20% of the body’s serotonin can be found in the central nervous system where it regulates many factors such as mood, sleep (including dreaming), muscle movements, and appetite (including digestion). The serotonin also is involved in cognitive functions such as learning and memory The serotonin chemical carries messages between different nerves. It can be found mostly in the brain, intestines, and blood. After an action potential, the serotonin is released by using the vesicle monoamine
Depression has similarities with anxiety, while also having tons of differences. But first, what is depression? Depression is caused by three neurotransmitters serotonin, norepinephrine, and dopamine. The definition of neurotransmitter is, “chemical messengers that allow the brain to communicate with the body” (Loudin). Neurotransmitter is basically a fancy doctor term that means a chemical in the brain that passes on messages to different parts of the brain. These three neurotransmitters are responsible for how happy someone
Depression and Happiness in human beings has been studied from multiple fields: psychology, biology, chemistry, philosophy, and other fields of note. Depression, which is characterized as a mental disorder, has been attempted to be explained with theories. These theories look at the a person’s environment, genetics, and even the chemical balances of their brain. Neurotransmitters, chemicals used by neurons to transmit signals, may have a significant impact on a person’s mood. One of these neurotransmitters, Serotonin, has been linked with depression.