Bradykinin Chinese name: bradykinin, English bradykinin, brady means slow. Bradykinin (BK) is a 9-mer substance with heart protective effects. It can reduce the infarct area of acute ischemic reinfusion heart, and medicine confirms that BK also has a delayed protective effect on ischemic reinfusion heart.

Introduction

1. Straight-chain 9-mer. It is a type of kinin. Its structure sequence is Arg, Pro, Pro, Gly, Phe, Ser, Pro, Phe, Arg. It has the effects of dilating blood vessels and lowering blood pressure.

2. Kininogenase functions on a class of partial growth hormone caused by kininogen. There are three main types: bradykinin, pancreatin, and methyldiastin, which are substances with the same structural basis under different kininase functions. Kininogenase is a glycoprotein with a molecular weight of 25,000 to 48,000, composed of 256 carbohydrates, and is widely distributed in tissues such as kidney, larynx, pancreas, sebaceous glands, and central nervous system, and can be released into the blood circulation. Kininogen is mainly produced by the liver and kidneys.

Clinical manifestations

Decrease: Decreased blood bradykinin is common in the decompensated stage of liver cirrhosis. Decreased bradykinin in urine is common in chronic glomerulonephritis, liver cirrhosis, and primary hypertension. BK is a heart protective factor. Previous studies have found that partial injection of BK before myocardial ischemia and during ischemic reinfusion can reduce the total area of myocardial infarction and decrease the incidence of arrhythmias during ischemic reinfusion. In addition, BK can also improve the oxidative phosphorylation of ischemic heart and increase the reserve of high-energy sulfate compounds and glycogen in the ischemic heart.

Recently, some experts and scholars have used BK B2 protein kinase gene knockout mice. They found that in these small animals, the angiotensin II converting enzyme inhibitor lacks the protective effect on cardiovascular diseases. This fully proves that the protective effect of angiotensin II converting enzyme inhibitors on cardiovascular diseases depends on BK. And there are references confirming that BK also participates in the early phase and long-distance protective effect of myocardial ischemia pretreatment. Recently, Ebrahim et al. successively found that BK has a delayed protective effect on ischemic reinfusion and also participates in the delayed phase of myocardial ischemia pretreatment. However, the delayed effect of BK on the oxidative phosphorylation of ischemic heart has not been reported. The study investigated the changes in oxidative phosphorylation during myocardial ischemia reinfusion in rabbits 24 hours after BK pretreatment.

The increase of bradykinin level can cause fever and has certain diagnostic significance for patients with myocardial infarction.