Bradykinin

Powerful vasodilator
Activated kallikrein (e.g. from saliva) acts on alpha-2 globulin in plasma → release kallin → converted by tissue enzymes to bradykinin

Net effect:
Secreted from endothelium
Stimulus
Inhibition
Site of action
Action (function) Vasodilation
↑ capillary permeability
↑ GFR