IMMUNOHISTOCHEMICAL DETECTION IN MARINE P LANARIA (PLATHELMINTHES TRICALDIDA) OF 5-HYDROXYTRYPTAMINE AND NEUROPEPTIDES RELATED TO THOSE FOUND VERTEBRATES

Antibodies raised against vertebrate peptides have been used in the st udy of invertebrates since more than 20 years. This has made it possib le to develop the molecular phylogeny concept, with all the carefulnes s required to avoid wrong interpretations due to unspecific cross-reac tions. It is now clearly established that some families of molecules a ppeared very early in the course of evolution, in primitive metazoan s uch as the cnidarians, whereas others were only detected in invertebra tes occupying higher positions in the phylogenetical tree. Among worms , many groups have been investigated. However, most studies have been focused on the description of the nervous system. In addition, reports concerning marine planarians are still rare. In order to contribute t o a more complete knowledge of the relationships between flatworms and other invertebrates, we studied two marine planarians Procerodes loba ta and, to a lesser extent, Sabussowia dioica, which are of interest b ecause of their primitive phylogenetic position. Several antibodies ra ised against leu- and metenkephalin, alpha-neo-endorphin, beta-endorph in, dynorphin 1-17, somatostatin, GRF, substance P, CCK-8s, FMRF-amide , and 5-hydroxytryptamine were tested on whole body worm sections. The results given by immunoreactions (IR) were compared with those obtain ed with histochemical technics used for neurosecretory products, and w ith the results reported by other authors for a diversity of species.