Neurotransmitters Function

of the chemical messenger dopamine, which affects parts of the brain that control reward and

Of the six most common neurotransmitters, dopamine is probably the one people know the most about. Dopamine is involved in controlling the reward and pleasure system in the brain. It allows us to recognize rewards and helps give us the ability to go after them. Learning, behavior, and cognition are also affected by dopamine levels. As with anything, if you have an imbalance, then bad things can happen. Parkinson’s disease can be caused by low dopamine amounts. People who have low dopamine levels can be addicted to substances easier.

A neurotransmitter is a chemical messenger that travels across the synapse between a neuron and another neuron, muscle fiber, or gland. Hormone is a chemical messenger of the endocrine system that is released by a gland or organ and travels through the blood. Neurotransmitter and hormone both compare because they both are chemical messenger, both chemicals are released from vessels into the surrounding fluid by similar mechanisms. They both work by binding to receptors on target cells. Neurotransmitter and hormones are very important systems, which regulate the various activities of the body, and are dependent on the release of special chemicals. Furthermore, the tissues in the Central Nervous System produce some hormones, as well as the neurotransmitters. What sets neurotransmitter and hormone apart? Neurotransmitters belong to the nervous system, however hormones belong to the endocrine system. Hormones and neurotransmitters are engendered differently; hormones are engendered by endocrine glands while neurotransmitters are engendered by neurons. The transmission of neurotransmitters is across the synaptic cleft, whereas that of hormones is by blood. Hormones are able to regulate their target organs, whereas neurotransmitters are able to stimulate the postsynaptic membranes. The action of neurotransmitters is extremely fast, which could be up to a few milliseconds. In contrast, effect of hormones could be lost for a long period, which could be in the range of few seconds to a few days.

The major support and refutation of the dopamine hypothesis has come from the examination of dopamine receptors in these regions of the brain. There are two main types of dopamine receptors, D1 and D2. However, within the category of D2 receptors, there are three subtypes, D2, D3, and D4. (5) Through PET scan analysis of dopamine usage in the brain and post-mordum molecular analysis of brain tissue, researcher were able to determine relative levels of dopamine receptors in patients with schizophrenia compared to non-schizophrenics. Overall analysis of dopamine

Dopamine is a neurotransmitter known to be involved in regulating mood and behaviour, amongst other things. Schizophrenia is associated with an overactivity of dopamine in the brain, and this may be associated with the delusions and hallucinations that are a feature of this disease.

The second neurotransmitter family includes amino acids, compounds that contain both an amino group (NH2) and a carboxylic acid group (COOH) and which are also the building blocks of peptides and proteins. The amino acids known to serve as neurotransmitters are glycine, glutamic and aspartic acids, all present in all proteins, and gamma-amino butyric acid (GABA), produced only in brain neurons. Glutamic acid and GABA are the most abundant neurotransmitters within the central nervous system, particularly in the cerebral cortex; glutamic acid tends to be excitatory and GABA inhibitory. Aspartic acid and glycine subserve these functions in the spinal cord (Cooper, Bloom, and Roth 1996).

But because they have a longer half-life and can rapidly cross the blood brain barrier, they are the choice of users. (Doweiko, 2014) Amphetamines and stimulants in general excite the CNS through stimulation of norepinephrine (Momaya, Fawal, & Estes, 2015), a neurotransmitter that helps, in conjunction with epinephrine to respond to the ?fight or flight? reaction to stress (Parse, 2015). Stimulants cause the release of norepinephrine from storage in sympathetic nerve endings. It then leads to the increase of arousal, heart rate, respiratory rate, and blood pressure. (Momaya, Fawal, & Estes, 2015) When taken orally, the stimulant is absorbed through the lining of the small intestine. It then reaches the brain through the bloodstream and produces regional effects. That is, it will cause a neurotransmitter activity in one region, while shutting of another region. Stimulants also seem to have an effect to alter the dopamine neurotransmission system. (Doweiko, 2014) The system is instrumental for movement and plays a role in Parkinson?s Disease when shut off. It also involves our pleasure center (rewarding properties), thus which is why we reach a euphoric state with certain stimulants. (Dopamine Neurotransmitter, 2015) (Steinkellner, Freissmuth, Sitte, & Montgomery,

Over the years, experiments have produced evidence to suggest that dopamine plays a role in the development of Schizophrenia (Howes, McCutcheon, & Stone, 2015). Dopamine is a neurotransmitter that is produced in the substantia nigra and ventral tegmental regions of the brain. The belief that dopamine was involved in Schizophrenia arose after multiple studies performed with compounds produced an increase in extracellular concentrations of dopamine (Lieberman, Kane, & Alvir, 1987). The patients that were administered these compounds had similar symptoms to those observed from patients who were diagnosed with Schizophrenia (Lieberman et al., 1987).

What do schizophrenia, Parkinson’s disease, bipolar disorder, and cocaine all have in common? It turns out they are all linked to the role of the dopamine transporter (DAT), which is an integral membrane protein responsible for the reuptake of dopamine from the synapse. Drugs that bind to DAT to prevent the reuptake of dopamine are used to treat the diseases mentioned above, among others. However, cocaine, which is also a DAT blocker, leads to profoundly negative effects, such as addiction and psychomotor stimulation. Understanding how different DAT blockers produce distinct behavioral and chemical responses could be the key to developing better drugs to treat dopaminergic disorders and also addiction to DAT blockers like cocaine.

Dopamine plays important roles in the brain and body. In the brain, dopamine functions as a neurotransmitter involved in reward-motivated behavior, motor control and controlling the release of various hormones. Dysfunctions of the dopamine system have been associated several important diseases including Parkinson's disease, attention deficit hyperactivity disorder, schizophrenia, and addiction [3]. Dopamine also functions in blood vessels, kidneys, pancreas, the digestive system, the immune system, and the blood vessels.

Dopamine is a neurotransmitter that controls brain reward and pleasure centers. It regulates body movement and your own emotional responses, and it enables people not only to see rewards, but to take action to move toward them, How dopamine makes us human, by Emily Deans M.D (2011). Unfortunately, dopamine deficiency can result in Parkinson’s Disease. Although dopamine is not used in treating Parkinson’s because the normal variant of dopamine does not cross blood to brain barrier, which is like a border that only allows certain substances to transfer from the blood into the brain. Instead scientists use Levodopa; which is a precursor 0f dopamine that can cross blood to brain barrier and converted to dopamine. People with low dopamine activity are more susceptible to addiction. The presence of one type of dopamine receptor is associated to sensation-seeking people, for example, adrenaline junkies.

Probably one of the most common forms of psychoactive drugs is stimulants. Stimulants are a class of psychoactive drugs that elevate mood, increase feelings of well-being, and increase energy and alertness. Nearly everybody has tried a stimulant and many people rely on them every single day. The best example of this is the drug caffeine, which is in many of the sodas or coffee we drink. Other forms of stimulants include: cocaine, methamphetamine, amphetamines, methylphenidate, nicotine, and MDMA. An additional common stimulant is nicotine, which is found in various types of tobacco. Stimulants change the way the brain functions by inhibiting neurons, which are nerve cells. These nerve cells communicate using neurotransmitters . One of the neurotransmitters they affect is dopamine, which makes people feel good. Dopamine can be released naturally by simply doing something you enjoy such as riding a bike or eating your favorite food. While these drugs may give the user pleasure, continual use may render their dopamine system useless. This will give the user little to no pleasure, which is often followed by an increased amount used in order to chase that high (NIDA).

Neurotransmitters are chemical messengers involved in signalling and transmission of nerve impulses across the synapses. They pass into the synaptic cleft through the membranes of the synapses and travel to the opposite membrane initiating an electrical stimulus. Glutamic acid is a neurotransmitter that plays a principal role in neural activation within the brain. It is also responsible for the taste sensation referred to as ‘umami’ that is associated with certain

Cocaine, on the other hand, has been found to have a profound effect on increased dopamine activity. Kennedy & Hanbauer (1983; cited in Karch, 2007) found a strong correlation between cocaine binding and the inhibition of dopamine uptake, and therefore proposed that dopamine transporters are binding sites for cocaine. Such research, which correlates strong reinforcing properties of cocaine with inhibition of dopamine transporters, suggests that cocaine has a more significant affect upon dopamine, than than it has upon serotonin and noradrenaline. The excessive role of dopamine can explain the high degree of pleasure that users of cocaine experience, as well as depression and cravings, which follow.

In the article “Dopamine and Teenage Logic” by Daniel Siegel he states that “Dopamine is a neurotransmitter central in creating our drive for reward” (Source B). This indicates that dopamine is one of the key causes of risk-taking. Teens often take risks because they are focused on the reward they get after they take it, rather than what would actually happen to them during and after they take the risk. There are two significant ways that dopamine affects our brains; increased impulsiveness, and the susceptibility to addiction by the release of dopamine.