RI is an abbreviation for'reuptake inhibitor. 'Reuptake inhibitors are a class of medication used to treat depression, anxiety, and other mental disorders. They change mood by altering the concentration of specific brain chemicals called as neurotransmitters. Specifically, reuptake inhibitors prevent neurons from removing neurotransmitters they have released, allowing more of them to remain active longer.
When you have depression, some of your nerve cells release too much of one neurotransmitter (such as serotonin) and others release too much of another (such as dopamine). Drugs that work by blocking receptors for both serotonin and dopamine allow for greater concentrations of each, resulting in better mood. The most common reuptake inhibitor used to treat depression is fluoxetine (Prozac). It works by increasing the amount of serotonin available at receptor sites, thus producing a calming effect on brain cells.
Inhibitors also are used in treatment of attention deficit hyperactivity disorder (ADHD). They work by preventing enzymes from breaking down dopamine, thereby causing it to be released into the synaptic gap between neurons where it will act as a signal to other neurons. Dopamine is responsible for feelings of pleasure; therefore, inhibiting its breakdown prevents these feelings from occurring.
Finally, inhibitors are used to treat obesity by preventing the body from absorbing up to 90% of the ingested fat through inhibition of reuptake pumps on cell membranes.
The "RI" in the acronyms SSRI and SNRI refers for "reuptake inhibitor." Reuptake inhibitors are a class of medication used to treat depression, anxiety, and other mental disorders. Specifically, reuptake inhibitors prevent neurons from removing neurotransmitters back into their cells, thus increasing their availability for longer periods of time. This increase in neurotransmitter availability may help restore normal emotional behavior.
Also read: How Do Prescription Drugs Work? A Neuroscientist Explains.
Because reuptake inhibitors reduce the reabsorption of some neurotransmitters, these drugs can boost their availability in the brain. As a result, more of these chemicals are able to reach their destination receptors, which causes them to have an increased effect.
For example, if serotonin (a mood-regulating chemical) is released from its storage site in the brain too quickly, it will be removed from the synaptic gap by reuptake proteins before it has time to interact with its receptor. A reuptake inhibitor like SSRIs prevents this process, allowing more serotonin to remain active for longer.
Similarly, dopamine is released when we experience something rewarding, such as eating chocolate or using cocaine. After it binds to its receptor, this information is passed on to other parts of the brain that control movement, emotion, and cognition. Dopamine plays two roles in this process: it is both the messenger that tells other parts of the brain that we have found something rewarding, and it is also responsible for making us feel happy. When someone takes a dose of a reuptake inhibitor like Paroxetine (the most common antidepressant in the world), they increase the amount of available dopamine in the brain. This leads to a reduction in negative feelings and an increase in motivation, energy, and pleasure sensitivity.
The reabsorption of a released material by the cell that created and secreted it originally. A selective serotonin reuptake inhibitor (SSRI) drug inhibits serotonin reuptake and hence affects the amount of serotonin in the brain. Reuptake is sometimes spelled re-uptake. In medicine, this process is usually desirable when trying to increase the amount of some substance in the body or reduce the amount of something harmful.
Serotonin is one of several neurotransmitters that are involved in mental activity. It is found mostly in neurons of the brain and spinal cord, but also in cells all over the body where it plays a role in controlling muscle contraction, blood pressure, sexual behavior, and other functions. Too much of a good thing is bad for you, though, and too much serotonin can be just as problematic as too little of it. When an individual takes SSRIs daily, they allow more of this neurotransmitter to stay in the synapses between neurons, thus improving mood while at the same time reducing the risk of developing depression or anxiety disorders that may arise from excessive amounts of serotonin.
SSRIs work by blocking the transporter proteins that move serotonin back into cells where it can be reused. They prevent serotonin from being taken up by these proteins so it stays in the synaptic space longer. This increases the amount of serotonin available for use by other neurons, which in turn improves mood.
Serotonin, for example, is affected by the reuptake process. Serotonin is a kind of neurotransmitter (a chemical messenger). In medicine, re-uptake refers to the process by which a neurotransmitter receptor returns to its original state after it has been activated by a ligand (a chemical messenger that binds to receptors). Thus, serotonergic neurons will continue to release serotonin even after they have contacted another neuron that expresses serotonin receptors. This action prevents excessive stimulation of these receptors and helps resolve any anxiety associated with withdrawal from SSRIs.
Reuptake also refers to the process by which antidepressants wash out of the body once they have been taken for several weeks or months. During this time, the drugs accumulate in the body's tissues where they continue to affect serotonin levels for some time after they are no longer being released into the bloodstream. As a result, patients who take these medications for long periods may need higher doses over time to achieve the same effect. This phenomenon is called "desensitization" or "downregulation" of serotonin receptors. Specifically, downregulation refers to a reduction in the number of receptors on cell surfaces where it becomes difficult to activate them again once the drugs are removed.
Neurotransmitters that are not absorbed by other neurons are absorbed by the nerves that produced them. This is known as "reuptake." SSRIs function by blocking serotonin reuptake, allowing more serotonin to be accessible for absorption by other neurons. This increases the amount of serotonin available for use by its target cells.
"Inhibition of serotonin reuptake" means that an inhibitor drug is preventing serotonin from being reabsorbed by nerve terminals, so there's more available for transmission to other neurons. As a result, less of the neurotransmitter is required to produce the same effect. Serotonin inhibition therefore produces a dose-response curve with smaller doses being sufficient to produce an effect.
In addition to antidepressants, substances found in certain plants have been shown to inhibit serotonin reuptake. These include khat (Papaver somniferum), which is used in some parts of Africa; grapefruit (Citrus paradisi); and St. John's wort (Hypericum perforatum). Although these substances do increase serotonin levels in the brain, they also cause various other effects, such as changes in mood, heart rate, and blood pressure, which make them unsuitable for use as antidepressants alone.
An inhibitor drug can only affect the amount of serotonin available at synapses. It has no effect on serotonin production or storage.