Bradykinin and neuronal injury.

Bradykinin, a nine-amino-acid peptide formed from a large precursor polypeptide (kininogen) by the action of the enzyme kallikrein (kininogenase), is the initial mediator of inflammation, and, in particular, bradykinin induces pain and alters vascular permeability. Bradykinin is one of the first compounds produced at the site of tissue injury and subsequently initiates a cascade of reactions that produce the cardinal features of inflammation. We will explore the role that bradykinin plays in various types of neuronal injury. In particular, we will focus on the role that bradykinin and other kinins play in brain and spinal cord trauma, in the pathophysiology of subarachnoid and intraparenchymal hemorrhage and ischemia, and in the initiation of nociceptive pain. This role suggests that bradykinin antagonists may be clinically useful in the therapeutic management of neurosurgical patients.