[The role of enzyme systems in the regulation of the "trigger" function of physiologically active peptides (review of the literature)].

Studies of enzymes, involved in metabolism of biologically active peptides, showed that the same substance may be used as a substrate of hydrolysis catalyzed by various peptidases. This principle should be applied for elucidation of polyfunctional properties of regulatory peptides, their ability to participate in dissimilar physiological responses. Investigation of the enzymatic step indicated also the pathways of possible neuropeptide level regulation within the definite regions of nervous tissue. The following principles are involved in evaluation of neuropeptides regulating functions: substrate specificity of particular peptidases, specificity of these enzymes in relation to their regional localization in brain or peripheric tissues, estimation of enzymatic activity in dynamics of physiological (pathophysiological) process. The examples are considered, which illustrate these points (principle "what-where-when") as well as data are discussed, which enabled to postulate the "trigger" function of neuropeptides (angiotensin II and bradykinin) in some long-term behavioral and somatic responses of a body.