Introduction

Abstract

In invertebrates, distribution of an ANG II-like substance has been studied immunocytochemically or chemically in four species: three annelids and one proto chordate. In annelids, an ANG II-like substance was found immunocytochemically in the nervous system of the leech, Theromyzon tessulatum, (Verger-Bocquet et all. 1992; Salzet et al. 1992, 1993), and the earthworm, Eisenia foetida, (Ohta, Haruta, Kobayashi, unpubl. data; Fig. 1.lA,B). Recently, Salzet (1995) found, using a chemical method, ANG II amide in the nervous system of the leech, Erpodella octoculata. This peptide was diuretic in the leech. Laurent et al. (1995) identified chemically an ANG I-like substance in the nervous system of Theromyzon tessulatum, and suggested the presence of a complete RAS in the leech. It is worth noting that ANG II injection induces water absorption through the foot (contact-rehydration) in the terrestrial slug, Limax maximus (Makra and Prior 1985). In protochordates, this peptide was demonstrated immunocytochemically in the spinal cord of the amphioxus, Branchiostoma belcheri (Uemura et al. 1994; Fig. l.1C). These findings suggest that biochemical processes generating ANG 1- and ANG II-like substances are widely distributed among invertebrates, especially in the nervous system.