Angiotensin receptors - evolutionary overview and perspectives

The structure of the angiotensin molecule has been well preserved throughou t the vertebrate scale with some amino acid variations. Specific angiotensi n receptors (AT receptors) that mediate important physiological functions h ave been noted in a variety of tissues and species. Physiological and pharm acological characterization of AT receptors and, more recently, molecular c loning studies have elucidated the presence of AT receptor subtypes. Compar ative studies suggest that an AT receptor subtype homologous to the mammali an type 1 receptor subtype (AT(1)), though pharmacologically distinct, is p resent in amphibians and birds, whereas AT receptors cloned from teleosts s how low homology to both AT(1) and AT(2) receptor subtypes. Furthermore, re ceptors differing from both the AT(1)-homologue receptor and AT(2) receptor exist in some non-mammalian species. This may suggest that the prototype A T receptor evolved in primitive vertebrates and diverged to more than one t ype of AT receptor subtype during phylogeny. Furthermore, phenotypic modula tion of AT receptors appears to occur during individual development/maturat ion. (C) 2001 Elsevier Science Inc. All rights reserved.