Brain Research Reviews 36 (2001) 35–45 www.elsevier.com / locate / bres Review The angiotensin system elements in invertebrates a, a a a b * Michel Salzet , Laurence Deloffre , Christophe Breton , Didier Vieau , Liliane Schoofs a ´ ´ Laboratoire d’ Endocrinologie des Annelides, UPRES- A 8017 CNRS, SN3, Universite des Sciences et Technologie de Lille, F-59655 Villeneuve d’ Ascq Cedex, France b Laboratory of Developmental Physiology and Molecular Biology, K. U. Leuven, Naamsestraat 59, B-3000 Leuven, Belgium, Tel.: 132-16-324-577, fax: 132-16-323-902 Accepted 8 June 2001 Abstract In this review, the different components of the renin–angiotensin system (RAS) in invertebrates are discussed. This system is implicated in osmoregulation, reproduction, memory processes and immune system regulation. As the elements of this hormone– enzymatic system also exist in invertebrates, it appears that the RAS originated very early in evolution.  2001 Elsevier Science B.V. All rights reserved. Keywords: Renin–Angiotensin System; Angiotensin-converting Enzyme; Invertebrates; Osmoregulation; Immune system; Memory Contents 1. Presence and localization in invertebrates .................................................................................................................................................. 36 2. Angiotensins: structural ........................................................................................................................................................................... 39 3. Synthesis and catabolism of angiotensin enzymes ...................................................................................................................................... 39 3.1. Renin-like enzyme .......................................................................................................................................................................... 39 3.2. ACE............................................................................................................................................................................................... 39 4. Receptors ................................................................................................................................................................................................ 41 5. Biological action ..................................................................................................................................................................................... 42 5.1. Osmoregulation............................................................................................................................................................................... 42 5.2. Memory processes........................................................................................................................................................................... 42 5.3. Reproduction .................................................................................................................................................................................. 42 5.4. Immune response modulation ........................................................................................................................................................... 43 6. Conclusion .............................................................................................................................................................................................. 43 Acknowledgements ...................................................................................................................................................................................... 43 References ................................................................................................................................................................................................... 44 The renin–angiotensin system (RAS) has long been acid bioactive peptide, angiotensin II (AngII), the final known to play a central role in body fluid homeostasis product. Angiotensin, first isolated and purified from [2,4]. In this signalling system, renin cleaves the essential- plasma [54], has been identified in many organs [9,14]. In ly inactive decapeptide angiotensin I (AngI) from an- vertebrates, peptides of the RAS family have been fully giotensinogen (AGT). After this, angiotensin-converting characterized from extracts of kidney and skin [20]. The enzyme (ACE) processes this peptide into an eight-amino- angiotensin peptides isolated from the peripheral nervous system are conserved in primary sequence, except for variations at positions 1, 3, 5 and 9 [56–60] (Table 1). The *Corresponding author. Tel.: 133-320-436-839; fax: 133-320-041- presence of angiotensins in the central nervous system 130. (CNS) has become widely accepted, notably with the E-mail addresses: michel.salzet@univ-lille1.fr (M. Salzet), liliane.schoofs@bio.kuleuven.ac.be. (L. Schoofs). finding of mRNA expression of AGT and renin in brain 0165-0173 / 01 / $ – see front matter  2001 Elsevier Science B.V. All rights reserved. PII: S0165-0173(01)00063-7