Bradykinin is formed by the interaction of factor XII, prekallikrein, and high-molecular-weight kininogen on negatively charged inorganic surfaces (silicates, urate, and pyrophosphate) or macromolecular organic surfaces (heparin, other mucopolysaccharides, and sulfatides) or on assembly along the surface of cells.

What is degradation of bradykinin?

Abstract. Bradykinin is rapidly degraded once it has been generated; this occurs most rapidly upon passage thru tissues such as the lung and it is also degraded in plasma or serum. Degradation of bradykinin in human plasma or serum appears to be mediated by two kininases.

Is kinin and bradykinin same?

The kinins have been implicated in the regulation of blood pressure, pain sensation and cell growth2. Apart from being a pro-inflammatory mediator, bradykinin is now recognized as a neuromediator and regulator of several vascular and renal functions.

Why do ACE inhibitors cause a dry cough?

ACE inhibition increases the cough reflex. The mechanisms underlying ACE inhibitor-induced cough are probably linked to suppression of kininase II activity, which may be followed by an accumulation of kinins, substance P and prostaglandins.

What drugs are inactive bradykinin?

Angiotensin-converting enzyme (ACE) is an enzyme that breaks down and inactivates bradykinin. ACE is present in the lungs and the kidneys and also converts angiotensin I to angiotensin II.

How does bradykinin affect blood flow?

Bradykinin, which promotes blood vessel dilation and a lowering of blood pressure, is inactivated. Conversely, angiotensin II production results in a host of events that increase blood pressure such as renal sodium retention, vasoconstriction and release of noradrenaline.

How does bradykinin cause coughing?

A local accumulation of bradykinin may lead to activation of pro-inflammatory peptides (e.g. substance P, neuropeptide Y) and a local release of histamine. This may also cause cough reflex hypersensitivity.

Is bradykinin a vasoactive peptide?

Bradykinin (BK) and Lys-BK are vasoactive peptides generated via the cleavage of kininogen by the action of kallikrein proteases. The effects of these peptides are mediated by two distinct G-coupled receptors.

What is kallikrein and kininogen?

Enzymes. Kallikreins (tissue and plasma kallikrein) are serine proteases that liberate kinins (BK and KD) from the kininogens, which are plasma proteins that are converted into vasoactive peptides. It can only activate kinins after being activated itself by factor XIIa or other stimuli.