The kinin-kallikrein system or simply kinin system is a poorly understood hormonal system with limited available research.[1] It consists of blood proteins that play a role in inflammation,[2] blood pressure control, coagulation and pain. Its important mediators bradykinin and kallidin are vasodilators and act on many cell types.
-Wikipedia Entry
Bradykinin activates several second messenger systems and thereby regulates blood-brain barrier permeability, blood pressure, pain perception, release of glutamate from astrocytes, neuronal differentiation and nitric oxide production3.