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A Brief Look of Catecholamine
10:41 on 26.3.2020

Catecholamines (CA) include norepinephrine (NA or NE), epinephrine (Ad or E), and dopamine (DA). The junction between sympathetic ganglion cells and effectors uses noradrenaline as a transmitter. Catecholamines are a neurological substance containing catechol and amine groups. Catechol and amine groups are combined by an enzymatic step of L-tyrosine at the site of sympathetic nerves, adrenal medulla, and pheochromaffin cells. Generally, catecholamines refer to dopamine, norepinephrine, and epinephrine. All three catecholamines are derived from tyrosine as a precursor.

 

Changes in plasma catecholamine levels indicate different pathological conditions. Two aspects can generally be determined from abnormal catecholamine levels:

Point 1 concerns adrenal medullary tumors, which combine with large amounts of catecholamines to cause circulatory disorders.

The second point concerns the cardiovascular system. Excessive levels of catecholamines can cause hypertension and myocardial infarction, and low levels often lead to hypotension. There are also potential links between differences in catecholamine levels and sudden cardiac death and coronary heart disease and heart congestion.

 

Clinical application:

  1. Shock, neurogenic, cardiogenic, and septic shock are commonly used in the early stages of dopamine to enhance myocardial contractility and expand peripheral blood vessels to improve microcirculation. Adrenaline is commonly used for anaphylactic shock. Dopamine anti-shock agent

 

Anabolic metabolism of catecholamines

The amount should not be too large. Generally, 2 mg is added to 500 ml of 5% glucose, and the intravenous drip rate is controlled at 4-8 micrograms per minute to maintain the systolic pressure at about 90 mmHg.

 

  1. Stomach bleeding, 1-3 mg of catecholamines are appropriately diluted and taken orally, and the gastric mucosal blood vessels are contracted due to local action in the stomach, resulting in hemostatic effects.

 

The adverse reactions are: ischemic necrosis can occur; so do not let the drug leak out of the blood vessel. Do not overdose; in order to avoid acute renal failure. In addition, the sudden drop of blood pressure may cause a drop in blood pressure. When the drug is stopped, the dose should be gradually reduced and the drip rate should be slowed down before the drug is stopped.

 

Pathological connection

Changes in plasma catecholamine levels indicate different pathological conditions. Two aspects can generally be determined from abnormal catecholamine levels:

Adrenal medullary tumors are involved first, and these tumors combine with large amounts of catecholamines to cause circulation disorders.

 

The second point concerns the cardiovascular system. (Catecholamines) excessive levels can cause hypertension and myocardial infarction, too low levels usually lead to hypotension. Different levels of catecholamines are also potentially linked to sudden cardiac death, coronary heart disease, and heart congestion.

 

When the sympathetic-adrenal medulla system is excited, catecholamines (CA) are released into the blood in large quantities. In various shocks, CA in the blood is tens or even hundreds of times higher than normal. Norepinephrine and epinephrine excite alpha receptors, causing the skin, abdominal organs, and renal small blood vessels to constrict, with less blood perfusion and microcirculation ischemia. Epinephrine can also excite beta receptors, making arteriovenous short circuits open, blood bypasses the real capillary network directly into the venules, aggravates tissue ischemia and hypoxia; arteriovenous short circuits of the pulmonary microcirculation open, affecting arteries of hypoxic venous blood To reduce PaO2.

 

Analytical method

The chemical structure of catecholamines is characterized by a dihydroxybenzene nucleus and an amino group-containing side chain. The content of catecholamines in biological samples is extremely low. Most literature reports that the content of catecholamines in actual biological samples is extremely low. Extremely poor stability and susceptibility to oxidation. In addition, various endogenous chemical interferences with similar structures and / or metabolites with the same chemical group in the biological sample are also present, leading to accurate determination of catecholamine concentrations in biological samples. It is difficult, highly selective and sensitive to determine a specific catecholamine substance in a biological sample, such as accurate determination of norepinephrine and / or epinephrine in serum, which is currently a difficult target to achieve in clinical practice. At present, related researches on the detection and analysis of catecholamines at home and abroad are continuously deepening, and more attention is paid to simple, easy, economical and applicable methods to accurately quantify related substances and can be widely applied.

 

Catecholamines are closely related to people's health and disease as neurotransmitters, and more and more evidence shows that they play different roles in physiological processes, disease occurrence and disease progression. Many clinicians and researchers have attached great importance to the study of catecholamines, and the most important research goal at this stage is how to quickly and accurately detect the target substance. The premise to obtain accurate results is to choose a simple and reliable analysis method. There are various methods for detecting catecholamines currently used in laboratories. At present, scholars have focused on the combination of high-performance liquid chromatography with electrochemical detection and fluorescence detection. Method for analysis of catecholamines. At present, these methods have their own advantages and disadvantages. The analysis characteristic of HPLC-electrochemical method is that it can reduce but not completely eliminate drug interference. In recent years, with the deepening of the research on CAs, many researchers at home and abroad have begun to combine the separation at the early stage with the detection steps at the later stage, so that a series of efficient, highly selective and sensitive CAs detection methods have been developed. Nikolajsen et al. Summarized the analysis methods of CAs in urine samples from 1988 to 2000. The analysis methods during this period were mainly based on high performance liquid chromatography (HPLC), chemiluminescence analysis (CL), and electrochemical analysis. ECD, capillary electrophoresis (CE), and fluorescence spectrophotometry (FL) are relatively few, especially LC-MS. Tsunoda et al. Summarized the analysis methods of CAs and their metabolites from 2000 to 2005. Parrot et al. Reported the detection of CAs and stimulating amino acids in the rat brain by capillary electrophoresis-laser induced fluorescence (CE-LIF). Jia Zhen et al. Reported the research progress of electrochemical analysis of CAs from 2000 to 2005. Dong Jie and others reviewed the characteristics of detecting CAs in tissue fluids and cells by fluorescence spectrophotometry, radiochemistry, gas chromatography (GC), high performance liquid chromatography, and electrochemical analysis.

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