Serotonin, also known as 5-hydroxytryptamine, is the main product of tryptophan metabolism. Serotonin is an important inhibitory neurotransmitter and intracellular messenger, which is widely distributed in the body and closely related to various physiological and pathological activities of the human body.
In the central nervous system, serotonin is usually distributed in the pineal gland and hypothalamus, participating in the regulation of pain and sleep and other physiological functions, such as inhibiting pain, promoting sleep, and also making the brain produce a sense of pleasure. Therefore, if you lack serotonin, you may have somatic pain, insomnia, and other symptoms. The abnormal content and function of serotonin in the central nervous system may also be related to the onset of many diseases. For example, when the content of serotonin decreases, depression may occur; When its function is abnormal, it may induce migraine.
In peripheral tissues, serotonin is a strong vasoconstrictor and smooth muscle contraction stimulator, which participates in the regulation of gastrointestinal motility and immune functions. For example, serotonin can stimulate receptors in gastrointestinal smooth muscle, cause gastrointestinal smooth muscle contraction, and accelerate gastrointestinal peristalsis.
Serotonin has certain pharmacological effects in clinics, for example, it can be used as an antidepressant to help improve and relieve anxiety, depression, and other bad emotions. It can also be used as a sleeping drug for people with mild sleep disorders to help alleviate insomnia and other conditions.
What is the difference between serotonin and heme?
Serotonin is a neurotransmitter, which can regulate people's moods and make people feel happy Some people's excessive need for serotonin causes them to overeat. Foods containing carbohydrates are easy to produce serotonin after digestion. That's why when a person is depressed... the heme in the human body is composed of four subunits, two of which are α Subunits and two β The four subunits of heme can be automatically assembled into α two β 2. Each subunit of heme is composed of a peptide chain and a heme molecule. The peptide chain will coil and fold into
What is the mechanism of action of serotonin?
The raphe nucleus in the brain stem is the nucleus with the largest density of 5-HT neurons in the mammalian brain. The cerebral cortex is the main projection area, and the densest nerve fibers project to the frontal cortex. There are also gun frontal cortex and motor cortex, mainly projecting from the dorsal raphe nucleus. The 5-HT neurons of the median suture and dorsal raphe nucleus contain highly parallel nerve fibers and project multiple terminal fields. This suggests that those functionally related nuclei may receive projections from the same group of 5-HT neurons or even from the same neuron. The modern classification of 5-HT receptors is based on their structural characteristics and the use of the second messenger system. 5-HT must be mediated by the corresponding receptor. The 5-HT receptor is complex, and seven subtypes of the 5-HT receptor have been found.
Among them, only 5-HT3 receptors are coupled with ligand-gated channel ion channels, and the other six are coupled with the G protein. Their structures include 7 transmembrane regions, 3 cytoplasmic rings, and 3 extracellular rings. 5-H has different pharmacological effects by activating different 5-HT receptors.
1. The role of the cardiovascular system is complex. Intravenous injection of microgram 5-HT can cause a three-phase reaction of blood pressure: ① transient decrease, which is related to 5-HT activating 5-HT3 receptor and causing negative cardiac frequency effect; ② Hypertension lasts for several minutes, which is caused by 5-HT activating 5-HT2 receptor and causing vasoconstriction of kidney, lung and other tissues; ③ Prolonged hypotension is caused by vasorelaxation of skeletal muscle, which requires the participation of vascular endothelial cells. In addition, 5-HT activates platelet 5-HT2 receptors, which can cause platelet aggregation.
2. The activation of the 5-HT2 receptor of gastrointestinal smooth muscle by smooth muscle 5-HT or 5-HT4 receptor of ganglion cells in the intestinal wall can cause gastrointestinal smooth muscle contraction, increase gastrointestinal tension and accelerate intestinal peristalsis; 5-HT can also excite bronchial smooth muscle, which is particularly sensitive to asthma patients but has little impact on normal people.
3. The injection of 5-HT into the lateral ventricle of nervous system animals can cause sedation, lethargy, and a series of behavioral reactions, and affect thermoregulation and motor function. Insect bites and prickles of some plants stimulate the release of 5-HT, which acts on sensory nerve endings, causing itching and pain. 5-HT itself has no clinical application value.
In clinical practice, selective serotonin reuptake inhibitors (SSRIs) and monoamine oxidase inhibitors (MAOIs) are used to increase the concentration of 5-HT in the synaptic space to treat many psychiatric symptoms of depression and compulsion. But there is a risk of serotonin syndrome.