{"id":12755,"date":"2019-12-13T22:13:05","date_gmt":"2019-12-14T06:13:05","guid":{"rendered":"https:\/\/selfhacked.com\/?p=12755"},"modified":"2020-09-12T01:05:34","modified_gmt":"2020-09-12T08:05:34","slug":"5-ht2c","status":"publish","type":"post","link":"https:\/\/selfhacked.com\/blog\/5-ht2c\/","title":{"rendered":"5-HT2C Receptors: What Are They, And What Do They Do?"},"content":{"rendered":"

5-HT2C<\/sub> receptors are one of many different types of serotonin receptors found throughout the brain. However, they have a number of key features that make them quite different from other serotonin receptors. Some early research also suggests that these receptors may play a role in some psychiatric disorders, such as depression and anxiety. However, there is still a lot we don\u2019t know about these particular serotonin receptors work, and what role they play in the brain! Read on to learn more about what the latest science currently has to say about 5-HT2C<\/sub> receptors, how they work, and how they might potentially be involved in various aspects of health and disease!<\/p>\n

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<\/a>Executive Summary<\/strong><\/span><\/h2>\n

5-HT2C<\/sub> receptors are a specific type of serotonin<\/a> receptor. They have a very wide range of different effects depending on where they are in the brain, as well as when- and how much they are stimulated.<\/p>\n

In general, they form one critical part of the brain\u2019s overall serotonin system, which wouldn\u2019t function properly without them.<\/p>\n

However, some research has associated relatively increased stimulation of these receptors with a variety of potentially negative effects, such as increased fatigue, reduced dopamine<\/a> levels and lower motivation, elevated stress reactivity (increased HPA axis<\/a> activity), undesired weight loss<\/a>, and lower insulin<\/a> levels.<\/p>\n

Additionally, 5-HT2C<\/sub> receptor over-activation has been potentially linked to some psychiatric disorders, such as OCD<\/a> and anxiety, although the exact role of these mechanisms are not fully clear yet.<\/p>\n

Some research suggests that inflammatory cytokines may be one of the important factors that can contribute to 5-HT2C<\/sub> over-activation – which may partially explain why these receptors have been reported to play a role in chronic fatigue syndrome<\/em> (CFS).<\/p>\n

Finally, some studies have reported that chronic over-activation of 5-HT2C<\/sub> receptors may contribute to disturbances in the circadian rhythm<\/em><\/a>, the \u201cmaster clock\u201d that your body relies on to regulate the sleep cycle and other important biological processes.<\/p>\n

While you probably wouldn\u2019t ever want to knock these receptors out entirely, there is some early evidence that there may be some \u201cnatural\u201d ways to counteract over-active 5-HT2C<\/sub> receptor activity. Doing so could – in theory<\/strong> – potentially alleviate some of the symptoms or effects associated with elevated 5-HT2C<\/sub> receptor activity, such as fatigue, low motivation, chronic stress, or mild anxiety.<\/p>\n

For example, some of the dietary and lifestyle factors that have been linked to reduced 5-HT2C<\/sub> receptor activity include social interaction, sexual activity, staying well-hydrated, and supplementing with fish oil<\/a> or curcumin<\/a> [R<\/a>, R<\/a>, R<\/a>]. However, this research is still in a very early stage, and no firm conclusions can be drawn yet until a lot more studies are done to investigate these effects in healthy human users.<\/p>\n

In the next few sections, we\u2019ll review what the latest science currently knows about some of the potential functions of these interesting receptors. However, keep in mind that much of this research is still in a very early stage, and very few solid conclusions can be drawn yet. A lot more research will be needed to verify all of the reported findings below – and in the meantime it is not recommended to try to alter or change your own 5-HT2C<\/sub> receptor activity by experimenting with supplements or other lifestyle changes! If you believe you might have any health symptoms or conditions that might involve 5-HT2C<\/sub> receptors, talk to your doctor in order to determine the best treatment approach to take for your individual medical needs.<\/p>\n

<\/a>What Are 5-HT2C<\/sub> Receptors?<\/span><\/h2>\n

While some serotonin receptors are found both throughout the central nervous system and the \u201cgut\u2019s nervous system\u201d (the enteric nervous system<\/em>), the 5-HT2C<\/sub> type of serotonin receptor is found exclusively in the brain [R<\/a>].<\/p>\n

They can be found in several locations, including the choroid plexus<\/em> (highest density), the nucleus of the solitary tract<\/em>, the dorsomedial<\/em> hypothalamus<\/em><\/a>, the paraventricular nucleus<\/em> (PVN) and the amygdala<\/em> (R<\/a>).<\/p>\n

The choroid plexus is responsible for the production of cerebrospinal fluid<\/em> (CSF), and it acts as a filtration system for removing metabolic waste, excess neurotransmitters, and any other foreign or toxic substances from the CSF (R<\/a>).<\/p>\n

Other brain areas with lots of 5-HT2C<\/sub> receptors, such as the hypothalamus, are highly involved in appetite and eating, sexual behavior, and regulating body temperature.<\/p>\n

Other regions, like the amygdala, are highly involved in emotions (such as anxiety).<\/p>\n

Based on this pattern of 5-HT2C<\/sub> receptor expression throughout the brain, these receptors are believed to play a role in many different functions and symptoms related to eating, anxiety, temperature regulation, sexual behavior and even the occurrence of seizures [R<\/a>].<\/p>\n

Another interesting and distinct feature of these receptors is that, unlike many other neurotransmitter receptors, 5-HT2C<\/sub> receptors appear to decrease in strength and number both when they are chronically stimulated or<\/em> chronically blocked. Some researchers have reported that these receptors can even be chronically activated without any actual serotonin molecules or other drugs binding to them, which deepens the mystery of how they work and exactly what they are doing [R<\/a>].<\/p>\n

<\/a>Possible Roles of 5-HT2C<\/sub> Receptors<\/span><\/h2>\n

<\/a>5-HT2C<\/sub> Receptors In Appetite, Eating Behavior, and Weight<\/strong><\/span><\/h3>\n

Some evidence suggests that 5-HT2C<\/sub> receptors may play a role in appetite and eating behavior<\/a>.<\/p>\n

For example, animal studies have reported that serotonergic drugs reduce total food intake in rodents, presumably by reducing appetite (or increasing satiety). Similar effects have also been reported in humans. These effects appear to be mediated, at least in part, by the 5-HT2C<\/sub> receptor (R<\/a>), which in turn works via the melanocortin-4 receptors (R<\/a>).<\/p>\n

In contrast, several common antipsychotic drugs are believed to block the 5-HT2C<\/sub> receptor, which may be one of the reasons why these medications are sometimes associated with weight gain in certain psychiatric patients.<\/p>\n

In addition to potentially reducing appetite, some evidence suggests that 5-HT2C<\/sub> receptor activation may also reduce the release of insulin<\/a> from the pancreas [R<\/a>]<\/p>\n

Finally, some 5-HT2C<\/sub> SNPs appear to determine levels of the appetite-related hormone leptin<\/em><\/a>, providing a potential mechanism underlying some of the genetic associations between 5-HT2C<\/sub> receptor genes with body weight and weight gain (R<\/a>).<\/p>\n

<\/a>5-HT2C<\/sub> Receptors and Other Neurotransmitters<\/strong><\/span><\/h3>\n

Activation of 5-HT2C<\/sub> receptors may affect the release of dopamine and norepinephrine<\/a> in certain areas of the brain. For example, 5-HT2C<\/sub> receptors have been reported to regulate dopamine release in the striatum, prefrontal cortex, nucleus accumbens, hippocampus, hypothalamus<\/a>, and amygdala, among others [R<\/a>].<\/p>\n

Some researchers believe that 5-HT2C<\/sub> receptors may also mediate the release of dopamine in response to certain common drugs, including caffeine<\/a>, nicotine<\/a>, amphetamines, morphine, cocaine<\/a>, and others (R<\/a>).<\/p>\n

<\/a>5-HT2C<\/sub> Receptors in Mood and Anxiety Disorders<\/strong><\/span><\/h3>\n

According to some early research, (over-)activation of 5-HT2C<\/sub> receptors may be associated with certain psychiatric disorders, such as depression and anxiety (R,<\/a> R<\/a>).<\/p>\n

Some other research has reported that suicide victims sometimes show an abnormally high number of 5-HT2C<\/sub> receptors in the prefrontal cortex, which adds suggestive evidence that 5-HT2C<\/sub> activation may be somehow involved in depression and suicide (R<\/a>).<\/p>\n

Additionally, preliminary findings from some animal studies suggest that 5-HT2C<\/sub> activation may be related to OCD, although additional research in humans would be needed to fully confirm this (R<\/a>, R<\/a>).<\/p>\n

Due to these potential links, some researchers have proposed that some psychiatric disorders, such as schizophrenia, may potentially be treated by using 5-HT2C<\/sub> activation to reduce levels of dopamine in the mesolimbic pathway of the brain (R<\/a>).<\/p>\n

However, much more research is still needed to fully clarify all of these effects, and the potential mechanisms that might be involved.<\/p>\n

<\/a>5-HT2C<\/sub> Receptors and Fatigue<\/strong><\/span><\/h3>\n

According to one early study, people with chronic fatigue syndrome<\/em> (CFS) reported lower perceived levels of fatigue when given medications that block the 5-HT2C<\/sub> receptor [R<\/a>].<\/p>\n

Relatedly, studies in animals have reported that mice lacking 5-HT2C<\/sub> receptors show more wakefulness-related behaviors – however, they also exhibit abnormalities in REM sleep<\/a> (R<\/a>).<\/p>\n

Conversely, activating 5-HT2C<\/sub> receptors in rats caused them to become less active overall, possibly indicating a fatigue-like effect (R<\/a>).<\/p>\n

Interestingly, because one of the factors that can activate 5-HT2C<\/sub> receptors are pro-inflammatory cytokines, some researchers have proposed that this may be one of the mechanisms that could explain some of the links between viral infections, chronic fatigue symptoms, and depression (R<\/a>).<\/p>\n

However, more research in humans will be needed to confirm these early findings.<\/p>\n