The document discusses the kinin-kallikrein system and its role in various physiological processes and diseases. It summarizes that bradykinin is a vasodilator peptide that increases capillary permeability and is involved in renal sodium regulation. Studies show that angiotensin-converting enzyme (ACE) inhibitors exert some of their cardioprotective effects through bradykinin, and these effects can be blocked by bradykinin receptor antagonists.