FROM POLYPLACOPHORA TO CEPHALOPODA - COMPARATIVE-ANALYSIS OF NITRIC-OXIDE SIGNALING IN MOLLUSCA

Citation
Ll. Moroz et R. Gillette, FROM POLYPLACOPHORA TO CEPHALOPODA - COMPARATIVE-ANALYSIS OF NITRIC-OXIDE SIGNALING IN MOLLUSCA, Acta biologica Hungarica, 46(2-4), 1995, pp. 169-182
Citations number
55
Categorie Soggetti
Biology
Journal title
ISSN journal
02365383
Volume
46
Issue
2-4
Year of publication
1995
Pages
169 - 182
Database
ISI
SICI code
0236-5383(1995)46:2-4<169:FPTC-C>2.0.ZU;2-Z
Abstract
The distribution of putative nitric oxide synthase (NOS)-containing ce lls has been analysed using NADPH-d histochemistry in the CNS and peri pheral tissues in more than 20 ecologically and systematically differe nt molluscan genera representing 3 main classes of the phylum MOLLUSCA : Polyplacophora (Lepidopleurus, Lepidozona, Katharina), Gastropoda (L ittorina, Lymnaea, Aplexa, Physa, Planorbarius, Planorbis, Helisoma, B iomphalaria, Helix, Limax, Cepaea, Bulla, Aplysia, Phyllaplysia, Phili ne, Pleurobranchaea, Tritonia Armina, Flabellina, Cadlina) and Cephalo poda (Octopus, Sepia, Rossia, Loligo). Several species were used for m ore detailed immunohistochemical, biochemical, biophysical and physiol ogical studies to further assay of NOS activity and to analyse functio nal roles of nitric oxide (NO) in these animals. The main conclusions of our comparative analysis and literature survey can be summarised as following: (i) There is strong evidence for the presence of NO-depend ent signalling pathways in different molluscan species. (ii) We hypoth esise that a general tendency in the evolution of NADPH-d-reactive cel ls in Mollusca is a migration of nitrergic function from periphery to the CNS. Also, different isoforms of NOS appear to be present in any o ne species. (iii) One of the Min functional targets of NO signalling i s the feeding system. However, there are obvious differences between p redators (many labelled central motoneurons) and herbivorous species ( many labelled peripheral putative sensory cells) as well as between la nd/freshwater and marine animals. Nevertheless, in all Species tested NO-activated feeding-like motor patterns in the buccal ganglia. Additi onal functional and cellular targets for NO in molluscs are also consi dered. We briefly review neuromodulatory mechanisms of NO action and w e consider molluscs as useful model systems for investigations of the roles of NO.