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Nitric oxide and human biological function

nitric oxide detector/no tester and human biological function

recently, it has been found that nitric oxide (no) is widely distributed in various tissues in organisms, especially in nerve tissues. It is a new type of biological messenger molecule, which was selected as a star molecule by American science magazine in 1992. No is an extremely unstable biological free radical with small molecule and simple structure. It is a gas at room temperature, slightly soluble in water, fat soluble, and can quickly diffuse through the biofilm. Its biological half-life is only S. its generation depends on nitric oxide synthase (NOS) and plays a very important biological role in cardiovascular, cerebrovascular regulation, neural, immune regulation and so on. Therefore, it is widely valued by people

1. Medical knowledge tells us that there are two important substances that act on vascular smooth muscle, norepinephrine and acetylcholine. Norepinephrine constricts vascular smooth muscle cells by acting on their receptors. It is not clear how acetylcholine acts on vascular smooth muscle to relax it, and the medical community is working together to study it

in 1980, American scientist furchaout found a small molecular substance in a study, which can relax vascular smooth muscle. Later, it was named as vascular endothelial derived relaxing factor (EDRF). It is an unstable biological free radical. EDRF is confirmed as No. As we all know, nitroglycerin is a drug for the treatment of cardiac gelatinization pain. For many years, people have been hoping to understand its therapeutic mechanism at the molecular level. Recent studies have found that nitroglycerin and other organic nitrates have no activity by themselves. They are first converted into no in the body. It is no that stimulates the formation of cGMP in vascular smooth muscle and dilates blood vessels. This effect is just similar to EDRF. In 1987, Moncada et al. Observed that the ED static torsion experimental machine is composed of the host, control and measurement system. RF needs to test more and more objects of vascular smooth muscle before it can be used for relaxation. At the same time, they measured the substance released by endothelial cells as no by chemical methods, and explained the degree of relaxation of vascular smooth muscle according to its content. In 1988, polmer et al. Proved that L-arginine (L-Arg) is the precursor of NO synthesis by vascular endothelial cells, thus establishing the concept that no can be synthesized in mammals

Biological role of

(1) role in the cardiovascular system no plays an important role in maintaining the constant tension of blood vessels and regulating the stability of blood pressure

under physiological conditions, when blood vessels are impacted by blood flow and the perfusion pressure suddenly rises, no, as a messenger of balance, maintains the relatively stable blood flow of their organs, so that blood vessels have self-regulation. It can reduce the average arterial blood pressure of the whole body, control the resting tension of various vascular beds of the whole body, and increase local blood flow. It is the main regulator of blood pressure

The possible mechanism for no to play a role in the cardiovascular system is to increase the activity of guanylate cyclase (GC) in cells, promote the cyclization of guanosine phosphate to produce cyclic guanosine monophosphate (CGMP), increase the level of cGMP in cells, and then activate cGMP dependent protein kinase to strengthen the phosphorylation of cardiac troponin I, and reduce the affinity of troponin C to ca2+, The activity of k+ channels on muscle cell membrane also decreased, resulting in vasodilation

(2) the research results on the role of no in the immune system show that no can be produced in a variety of cells in the human body. For example, when endotoxin or t-differential sensor extensometer [linear variable differential] cells activate macrophages and polymorphonuclear leukocytes, they can produce a large number of inducible NOS and superoxide anion radicals (), thus synthesizing a large number of no and H2O2, which plays a very important role in killing invading bacteria, fungi and other microorganisms and tumor cells, organic foreign bodies and inflammatory damage

it is currently believed that no released by activated macrophages can kill target cells by inhibiting the tricarboxylic acid cycle, electron transport and cellular DNA synthesis in the mitochondria of target cells

no produced by immune response also has toxic effects on adjacent tissues and cells that can produce Nos. Some local or systemic tissue damage related to the immune system, abnormal expansion and permeability of blood vessels and lymphatic vessels may be closely related to the local content of No

(3) the study on the role of L-Arg → no pathway in the central nervous system (CNS) believes that no acts on adjacent peripheral neurons, such as protruding anterior nerve endings and astrocytes, and then activates GC to improve the level of cGMP, resulting in physiological effects. For example, no can induce long-term potentiation (LTP) related to learning and memory, and act as an inverse messenger in its LTP

continuous stimulation of ascending and parallel fibers in the cerebellum can cause long term depression (LTD) of nerve conduction in parallel fiber cells, which is considered to be a mechanism in cerebellar motor learning system, and no is involved in this mechanism

L-Arg → no pathway also exists in the peripheral nervous system. No is considered to be a transmitter or mediator of non cholinergic and non adrenergic nerves, which participates in the process of pain afferent and sensory transmission

it is also reported that no plays an important mediating role in gastrointestinal nerve mediated relaxation of gastrointestinal smooth muscle. In the gastrointestinal plexus, NOS and vasoactive intestinal peptide coexist and can cause nonadrenergic non cholinergic (NANC) relaxation, but antibodies to vasoactive intestinal peptide can only partially eliminate the relaxation of NANC, and the rest of the relaxation reaction can be eliminated by n-methylarginine

no, as a neurotransmitter of NANC neurons, plays an important role in the urogenital system. It has become a regulating substance for physiological functions such as urinary continence, which provides a theoretical basis for the drug treatment of urogenital diseases

it has been proved that the nervous system with no as transmitter widely exists in human body, which is as important as adrenergic, cholinergic and peptide nerves. If its function is abnormal, it may cause a series of diseases

3. Chemical behavior of nitric oxide detector/no tester

no is a gas at room temperature, and its fat solubility is one of the possible factors that make it a messenger molecule in human body. It can quickly diffuse through the biofilm without any intermediary mechanism, and transmit the information produced by a cell to the surrounding cells. The main influencing factor is its biological half-life. It has a variety of biological functions because it is a free radical, which is easy to participate in and transfer electron reactions and join the oxidation-reduction process of the body. The molecular coordination makes it have high affinity with heme iron and non heme iron to replace the positions of O2 and CO2. According to research reports, hemoglobin no can lose its nearby bases and become free heme no, which means that free bases can freely participate in the catalytic reaction, free proteins can freely change the conformation, and free heme can freely diffuse out of proteins. Any of these three changes or their combination will play an important role in the activation process of guanylate cyclase

The biological role and mechanism of no are in the ascendant, and its discovery suggests the prospect of inorganic molecules in the field of medicine. The author believes that more inorganic molecules will be found, studied and applied in the research field of promoting human health

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