Protein-peptide complexes of angiotensins in the mechanisms of thirst motivation.

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.