Neurotransmmitteers

When substances like Acetylcholine (Ach) and norepinephrine which are small- molecular neurotransmitters are released into the body they bind to receptors on tissue or neurons through our ANS and PNS system. Ach is released by many PNS neurons and some CNS neurons. In the PNS Ach is an excitatory neurotransmitter at some synapses, such as the neuromuscular junction where it binds to ionotropic receptors which open cation channels. Ach can also be an inhibitory neurotransmitter at other synapses, where it binds to metabotropic receptors while opening potassium channels. The enzyme acetylcholinesterase (AchE) inactivates Ach by splitting into acetate and choline fragments. Norepinephrine (NE) is a biogenic amine; most biogenic amines may cause

There are three ways in which a drug can affect a neurotransmission, such its synthesis, storage, and release. An agonist drug that affects synthesis would monoamine oxidase inhibitors because they inhibit the breakdown of serotonin at the serotonin neural

The cerebral cortex directs functions like speech, behavior, reactions, movement, thinking, and learning. In fact, some research suggests that bipolar disorder originates with problems with the thalamus, which links sensory input to good and bad feelings. The hippocampus also affects depression. It, like the amygdala, is part of the limbic system. It is vital in processing long-term memory. This section of the brain registers recurring fear. In people with clinical depression, the hippocampus is much smaller. Research suggests, even, that ongoing exposure to stress impairs the growth of nerve cells in this part of the brain. One of the most important jobs of the brain is to process senses, through neurons. Neurotransmitters are specific substances that help relay information to the brain. Scientists have identified many neurotransmitters that affect depression. A lack or excess of the neurotransmitters acetylcholine, serotonin, norepinephrine, dopamine, glutamate, lithium carbonate and gamma-aminobutyric acid are thought to contribute to depression. Acetylcholine is involved in learning and enhances memory. Serotonin helps regulate sleep, appetite, and mood, and inhibits pain. Research shows the idea that many depressed people have reduced levels of serotonin. Low levels of a byproduct of serotonin have been linked to a high risk for suicide. Norepinephrine is a neurotransmitter which constricts blood vessels and raises blood pressure. An excess in

Serotonin, (or 5-hydroxytryptamine) is a neurotransmitter released by neurones in the brain. It is a chemical responsible for good mood and well-being. Therefore one of the possible causes of depression is a chemical imbalance of Serotonin levels in the brain and consequently, ineffective neuronal transmission at the synaptic cleft. (Lovatt, 2010) This has negative implications on mood, sleep and appetite.

The third neurotransmitter family is composed of peptides, compounds that contain at least two and sometimes as many as 100 amino acids. Peptide neurotransmitters are poorly understood: Evidence that they are, in fact, transmitters tends to be incomplete, and restricted to their location within nerve terminals, and the physiologic effects produced when they are applied to neurons. Probably the best understood peptide

The belief is that antidepressants work by increasing levels of a group of chemicals in the brain called neurotransmitters. Certain neurotransmitters, such as serotonin and noradrenaline, can improve mood and emotion, although we do not yet fully understand this process

Gamma-Aminobutyric acid commonly referred to as GABA, and glutamate make up around 80 percent of the neurotransmitters found in brain. GABA dampens the activity in the brain while

Every day, your brain maintains a delicate balance between chemicals that push its cells to fire and opposing chemicals that pull its cells back toward inactivity. Two of the most common neurochemicals that play this tug of war are glutamate and GABA, both of which are classified as neurotransmitters, chemical messengers that communicate between neighboring brain cells. The purpose of glutamate is to elicit action, while the function of the GABA neurotransmitter is to restore calm.

Most people usually think of the brain or heart being the most important part of our body. While they are indeed important, they would be entirely useless if certain substances called neurotransmitters didn’t exist. Neurotransmitters are substances in our body that carry signals from one nerve cell to another. Without these neurotransmitters in our body, we wouldn’t receive crucial signals such as telling our heart to beat. Six of the most common neurotransmitters in our body are dopamine, serotonin, endorphins, norepinephrine, acetylcholine, and gamma-aminobutyric acid (GABA).

(3) While successful drug therapies which act on neurotransmitters in the brain imply that depression is a neurobiological condition (4), the fact that such medications do not help about 20 percent of depression-sufferers seems to show that not all depression is due to such imbalances. Rather, depression is not caused by one single factor; it is most often caused by many different things. Genetics, biochemical factors, medicines and alcohol, developmental and other external factors, and relationships, marriage and children all have effect on the development of clinical depression. (5) The strongest hypotheses on the pathways to depression are in decreases in the activity of specific neurotransmitters, or the overactivity of certain hormonal systems. (3)

Other drugs, such as amphetamine or cocaine, can cause the nerve cells to release abnormally large amounts of natural neurotransmitters or prevent the normal recycling of these brain chemicals. This disruption produces

The leading theory explaining the biology of depression is the monoamine hypothesis of depression. (Stahl, 3) This theory suggests that depression is caused by a deficiency in one or another of the three neurotransmitters: serotonin, norepinephrine and dopamine. The theory was formulated after the accidental discovery of the original drugs for depression and psychosis, much in the same way Fleming discovered penicilin.

Many psychiatric and psychoactive drugs that are available on the market, pharmaceutically or illegally, closely resemble neurotransmitters and are actually able to mimic it to the extent that it fools the receptors. Basically, these drugs hijack the neurotransmitters. Once these drugs are ingested, it enters into the brain, gets into the synapse and binds itself to the receptor. This then causes the inappropriate release of neurotransmitters and alter the breakdown and recycling of neurotransmitters or can be used to destroy particular neurotransmitters completely (Sapolsky, 2005, p. 14).

Neurotransmitters involved in depression include norepinephrine, dopamine, and serotonin. An imbalance of hormones may also play a role in depression. Many depressed people have higher than normal levels of hydrocortisone, a hormone secreted by the adrenal gland in response to stress. In addition, an underactive or overactive thyroid gland can lead to depression.4

The neurotransmitters norepinephrine, serotonin is also thought to play a role in depression (Porth 1371).  There are decreased levels of these neurotransmitters present in the pre and post synaptic cleft.  Dopamine levels have been studied and increased levels of dopamine are found in mania and decreased levels in depression (Porth 1372).