No abstract

A comparative analysis of the physiological actions of native angiotensin I and angiotensin II and protein-peptide complexes of angiotensin I and angiotensin II on drinking behavior in rats was performed. The protein-peptide complexes of angiotensin I and angiotensin II had wider spectra of physiological activity than the native peptides. Protein-conjugated angiotensin I, unlike the motivationally neutral native angiotensin I, produced marked activation of innate drinking behavior in mice. The protein-peptide complex of angiotensin II showed selective effects on acquired drinking behavior. These data are assessed with respect to the specific involvement of protein-peptide complexes of angiotensin I and angiotensin II in the mechanisms of thirst motivation during the performance of innate and acquired habits.

We compared physiological activity of synthetic complexes from angiotensin IV and functionally different proteins (transport protein, bovine serum albumin; and neurospecific Ca(2+)-binding protein, S100b) as model analogues of endogenous protein-peptide complexes. Physiological activity of angiotensin IV was specifically modified by these proteins. Our results suggest that complexes of angiotensin IV with bovine serum albumin and S100b are strong factors for the integration of central and peripheral functions at the homeostatic and behavioral level.

We compared physiological activity of synthetic analogues of endogenous protein-peptide compounds, complexes of angiotensin II(1-7)with functionally different proteins (transport protein, serum albumin; and neurospecific Ca(2+)-binding protein, S100b). Physiological activity of angiotensin II(1-7)was shown to depend on the type of a carrier protein. Our results suggest that complexes of angiotensins with BSA and S100b are strong factors for the integration of central and peripheral functions at the homeostatic and behavioral level.

Changes in blood glucose levels are paralleled by modification of normal activities of angiotensin II and angiotensin IV. Hypo- and hyperglycemia similarly reduced the hypertensive effect of angiotensin II and similarly distorted the initial hypotensive effect of angiotensin IV. Presumably, the adaptation and compensatory processes in the renin-angiotensin system under conditions of shifted homeostatic constants manifest by phenomena of external reintegration and redistribution of functions of its individual peptide components. This provides restructuring of the mechanisms of intra- and intersystemic organization of physiological functions under extreme conditions.