What is Sympathetic Medicine?

Sympathetic ganglion blocking drugs are also called antisympa-thicomimetic drugs. Acts on the sympathetic ganglia, depletes the storage of transmitters in the sympathetic nerve endings, blocks the transmission of the excitability of the sympathetic nerves, thereby relaxing the arterioles, venules, and smooth muscles, reducing peripheral resistance, reducing cardiac output, and producing a powerful hypotensive effect . The sympathetic nervous system plays an important role in the pathogenesis of hypertension. Due to its wide range of functions, it is currently rarely used in clinical applications ^[1] .

Sympathetic ganglion blocking drugs are also called antisympa-thicomimetic drugs. Acts on the sympathetic ganglia, depletes the storage of transmitters in the sympathetic nerve endings, blocks the transmission of the excitability of the sympathetic nerves, thereby relaxing the arterioles, venules, and smooth muscles, reducing peripheral resistance, reducing cardiac output, and producing a powerful hypotensive effect . The sympathetic nervous system plays an important role in the pathogenesis of hypertension. Due to its wide range of functions, it is currently rarely used in clinical applications ^[1] .

Chinese name

Sympathetic ganglion blocker

Foreign name

antisympa-thicomimetic drugs

Central antihypertensive drugs

During the central regulation of hypertension, impulses issued by baroreceptors are projected to the ventrolateral medulla and solitary nucleus, and blood pressure is adjusted by regulating the outgoing impulse of the sympathetic nerve. Previously, it was thought that in the central nervous system, only 2 receptors exist, and traditional central antihypertensive drugs lower the blood pressure by stimulating 2 receptors to cause a decrease in outgoing sympathetic nerve activity. The latest research found that 2 receptors mainly exist in the solitary nucleus and the blue spot nucleus, and the ventrolateral nucleus is mainly an I1-imidazoline receptor. Stimulating this receptor not only causes a decrease in the outgoing activity of the sympathetic nerve, but also has a drainage and diuretic effect. And cooperate to step down. Central sympathetic nervous system antihypertensive drugs that act on these two types of receptors are commonly referred to as central antihypertensive drugs ^[2] .

(1) 2 receptors are mainly distributed in the medullary cardiovascular axis, solitary nucleus, vagus nucleus and peripheral sympathetic nerve endings before and after the synaptic membrane. The central 2 receptor excitement has the following 4 effects: reduced sympathetic nerve impulses, slowed heart rate, and vascular smooth muscle relaxation; lethargy in the body; reduced saliva secretion; increased growth hormone secretion. Representative drugs include clonidine, methyldopa, others include guanfacine, guanabenz. Taking clonidine as an example, it is mainly used for patients with hypertension of moderate to severe hypertension and glaucoma, which is rarely used as first-line medication in combination with other antihypertensive drugs; it is also used for migraine, severe dysmenorrhea, and postmenopausal hypertension And glaucoma patients can also be used for rapid withdrawal of hypertensive emergencies and opioid addiction. At present, clonidine transdermal patches are used in China to treat children with ADHD.

(2) Non-adrenergic imidazoline I1 receptor agonists in the body. I1 receptors are mainly distributed in the ventral anterolateral brainstem, hippocampus, hypothalamus, and striatum, and are located on the plasma membrane of neurons. After the I1 receptor is excited, it inhibits peripheral sympathetic nerves, leading to peripheral vasodilation, drainage of sodium and drainage, and a hypotensive effect. Representative drugs include Limenidine and Moxonidine. Taking Limenidine as an example, it has recently been found that its selectivity for the I1 receptor is 2.5 times greater than that for the 2 receptor. Combined with other drugs as first-line antihypertensive drugs, it can also be used for the treatment of refractory hypertension. This medicine has a small effect on cardiac hemodynamics and can be used to treat withdrawal symptoms after morphine addiction.

Ganglion blocker

By blocking the sympathetic ganglion and lowering blood pressure, the effect is fast and strong. Because the parasympathetic ganglion is blocked at the same time, the adverse reactions are many and serious, and orthostatic hypotension and tolerance are prone to occur. It is basically not used at present and is only occasionally used for critical situations such as hypertension crisis, hypertensive encephalopathy, and surgery Controlled hypotension during surgery to reduce bleeding during surgery. The representative medicines are camphor (fenoflavone), meclarmin (mecanamine), etc. ^[2] .

Norepinephrine blocking agent

Acting on the noradrenergic nerve endings, it affects the processes of synthesis, storage, release and reuptake of transmitters, and blocks the regulation of the heart and blood vessels by noradrenergic nerves. There are many adverse reactions to this kind of drugs, and they are no longer used alone. They are only used as one of the components of some traditional antihypertensive compound preparations. In addition, this class of drugs is an important tool for studying sympathetic nerve activity. Such as reserpine, guanethidine, etc. ^[3] .

(1) Guanethidine. Can hinder the release of norepinephrine from the sympathetic nerve endings, and deplete the storage of norepinephrine, thereby preventing nerve transmission from the nerve endings after the adrenergic ganglia, which can reduce peripheral resistance, lower blood pressure, and slow heart rate and cardiac output. decrease. Usage: The dose is 10 mg orally, once a day, and can be gradually increased to 50 mg per day. The antihypertensive effect is relatively large, and there are more adverse reactions, such as orthostatic hypotension, dry mouth, diarrhea, nasal congestion and impotence. It can only be used in patients with severe hypertension and other antihypertensive drugs.

(2) Reserpine. It belongs to the genus Roufu, which can reduce the levels of catecholamines in the brain and internal organs, thereby hindering and depleting the neurotransmitting substances at the end of the sympathetic nerve, so as to reduce peripheral resistance and blood pressure. Have central sedative effect. The effect of this product is mild, and the effect is slow. Usually, it only gradually takes effect within 1-2 hours after the first medication, and the effect lasts for 24-48 hours. The peak of the drug effect is 1-2 weeks after the medication. Usage: The dosage is 0.25 mg, orally, 3 times a day. This medicine has a central obstructive effect. It is forbidden to use in patients with depression. It can improve gastric secretion and cause gastrointestinal bleeding. Those with original ulcers should be used with caution. Adverse reactions: nasal congestion, bradycardia, fatigue, long-term use can lead to elevated blood lipids. Because there are many adverse reactions, it is no longer the first choice for antihypertensive drugs.

Epinephrine receptor blocker

(1) 1 receptor blocking drugs: such as prazosin and terazosin. 1 blockers are generally not used as first-line drugs for the treatment of hypertension. The biggest advantage of this drug is that it has no obvious adverse metabolic reactions and can be used in patients with hypertension such as diabetes, peripheral vascular disease, asthma and hyperlipidemia. Doxazosin and tramazosin are less fat-soluble than terazosin, and have an affinity for 1 receptors that is 1/2 or less of prazosin. Terazosin's blood pressure is moderately reduced, the duration of action is long, and the orthostaticity Low blood pressure, usually can maintain continuous blood pressure for 24 hours. For patients who are still not satisfied with blood pressure control after sufficient or combined application of diuretics, blockers, CCB, ACEI, ARB, etc., combined application options can be considered. Sexual alpha1 blockers ^[2] .

(2) Alpha and beta receptor blockers. At present, drugs that have both and receptor blocking effects are gradually being widely used. On the one hand, the peripheral blood vessels are dilated, the vascular resistance is reduced, the blood pressure is reduced, and the sympathetic tone reflex increase is prevented; On the other hand, through non-selective blocking of receptors, it can slow heart rate, inhibit myocardial contractility and reduce cardiac output. Its antihypertensive effect is mainly caused by -blockers at low doses, and at high doses mainly by 1 blockers. Therefore, and receptor blockers have good prospects in the treatment of hypertension. Commonly used alpha and beta blockers include: Labelol, which has a ratio of alpha and beta blockers of 1: 3 (intravenous) and 1: 7 (oral); arolol and card For Veldiro, the ratio of and blockers is 1: 8. Among them, arololol has a strong effect, and has a balanced blocking effect on and receptors in patients with hypertension. It can inhibit peripheral vasoconstriction caused by vasoconstriction and increase blood pressure. The antihypertensive effect is better than the other two drugs. In addition, because alorolol has a more significant heart rate slowing effect than the other two drugs, it is often used in the treatment of hypertension with tachycardia. Labelol has an intravenous preparation, which can be used for antihypertensive treatment in patients with hypertensive emergencies, hypertension during perioperative fasting and pregnancy-induced hypertension. Carvedilol and arololol can also be used for the treatment of arrhythmias ^[2] .

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