A Possible Role in Blood Pressure Regulation

During the last decade, the actions of central nervous system peptides on blood pressure and volume homeostasis have been the subject of intense investigation. There is evidence that central mechanisms of cardiovascular control could be modulated by brain peptides. Kinins are biologically active peptides released from kininogen by either glandular or plasma kallikrein. Kinins in the central nervous system, released by glandular (tissue) kallikrein, may act at or near their site of origin. Components of the kallikrein-kinin system are found in a variety of tissues, among them the central nervous system. An enzyme that has the physical and chemical characteristics of glandular kallikrein has been identified in the rat brain. Kininogenase activity and immunoreactive glandular kallikrein have been shown to be similarly distributed within the brain. The presence of a messenger RNA (mRNA) coding for tissue kallikrein has been documented in both whole brain and discrete regions therein.Thus, the presence of mRNA functionally able to direct kallikrein synthesis, immunoreactive kallikrein, and kinin-forming activity in the brain indicates that the kallikrein-kinin system is present there as well.