What are the functions of dopamine?

The hearts, blood vessels and blood pressure of many people are unstable, and they often suffer from various diseases, especially unhealthy kidneys, which lead to low renal blood flow and problems with glomerular filtration function. At this time, you can increase adrenaline by supplementing dopamine, which can enhance kidney function, improve heart function recovery, and greatly help dredge blood vessels and balance blood pressure. Dopamine has a good effect, but it is a Western medicine after all, so you must be careful with the dosage, usage and indications.

What is the pharmacological action of dopamine?

1. The heart mainly stimulates the cardiac β1 receptors and also releases norepinephrine, which can enhance contractility and increase cardiac output. Normal doses have little effect on heart rate, but large doses can speed up heart rate. Compared with isoproterenol, dopamine has a weaker effect on increasing cardiac output, has less effect on heart rate, and is less likely to cause arrhythmias.

2. Blood vessels and blood pressure can act on the α receptors and dopamine receptors of blood vessels, but the effect on β2 receptors is very weak. Dopamine can increase systolic blood pressure and pulse pressure, but has no effect on diastolic blood pressure or slightly increases it (Figure 10-2). This may be the result of increased cardiac output, decreased renal and mesenteric arterial resistance, and a slight increase in other vascular resistance, resulting in little change in total peripheral resistance. The vasodilatory effect of dopamine cannot be antagonized by beta-blockers, atropine, and antihistamines, so it is believed that it acts selectively on dopamine receptors (D1 receptors) in blood vessels. Large doses of the drug mainly cause vasoconstriction, which leads to increased peripheral resistance and increased blood pressure. This effect can be counteracted by α-receptor blockers, indicating that this effect is the result of stimulating α (α1 receptor) receptors.

3. Kidney dopamine can dilate renal blood vessels, increase renal blood flow, and increase glomerular filtration rate. It has a natriuretic and diuretic effect, which may be due to the direct effect of dopamine on renal tubular dopamine receptors. When used in large doses, it can also cause significant constriction of renal blood vessels.

How dopamine works

⑴ Small dose (0.5-2ug per minute based on body weight)

kg), mainly acts on dopamine receptors, dilates renal and mesenteric blood vessels, increases renal blood flow and glomerular filtration rate, and increases urine volume and sodium excretion;

⑵ Small to medium dose (2-10ug per minute based on body weight)

㎏), can directly stimulate β1 receptors and indirectly promote the release of norepinephrine from the storage site, produce positive stress on the myocardium, increase myocardial contractility and stroke volume, and ultimately increase cardiac output, systolic blood pressure, and possibly pulse pressure, with no change or slight increase in diastolic blood pressure, and usually no change in total peripheral resistance, while coronary blood flow and oxygen consumption improve;

⑶ When the dose is large (greater than 10ug per minute based on body weight)

kg), stimulating α receptors, leading to increased peripheral vascular resistance, renal vasoconstriction, and reduced renal blood flow and urine volume. Due to the increase in cardiac output and peripheral vascular resistance, both systolic and diastolic blood pressure increase.