The Comparative Anatomy Study Of Invertebrate Nervous System

The general anatomical character and microstructure character of nerve system of 12 invertebrates ( Planocera reticulata, Baseodiscus curtus, Linens sp., Nereis pelagica, Pheretima tschiliensis, Acanthochiton rubrolineatus, Cellana toreuma, Neverita didyma, Mactra chinensis, Squilla oratorio, Gaetice depressus, Oxya chinensis ) were studied with histological method. The results indicate that the ganglion of invertebrate is form with a peripheral region of cell bodies and a centre region of neuropil. The proportion of cell body region in ganglion was measured use biological stereology method with image analysis software ImageProPlus v4.5. The ratio of cell body region was highest in Mollusc, Cellana toreuma 26.18%, Neverita didyma 28.13%, Mactra chinensis 27.53%. This may be the express in nervous system of mollusc with passive defense strategy, low motor ability and lack of developed sense organ, in environmental adaptation. The ratio of cell body region was lowest in crustacean, Squilla oratorio 11.43%, Gaetice depressus 15.53%. The ratio of Planocera reticulata, Pheretima tschiliensis and Nereis pelagica was 19.00%, 20.13% and 12.82%. The conclusion of this study is the animal with strong motor ability and developed sense organ has little neuron body and more neuropil in ganglion. On the contrary, the animal with poor motor ability and undeveloped sense organ has more neuron body and little neuropil in ganglion. On this account, the general morphologic structure character of nervous system reflects the adaptation to environment and has little relation with the phylogeny of animal.The protein sequence of NOS from 25 difference animals was alignment use clustalW and MEGA software. The amino acid sequences of NOS have apparent difference and have conservative property in some important domain. The variance of this molecule is correlated to the phylogeny of these animals. The NOS was a perfect molecule use to analysis the phylogeny of animal.The distribution of putative nitric oxide synthase (NOS)-containing cells has been analysed using NADPH-diaphorase histochemistry in the centre nervous system and peripheral tissues in more than 20 ecologically and systematically different genera representing 5 main phylum of invertebrates: Platyhelminthes (Euplanaria gonocephala, Planocera reticulata), Nemertinea(Baseodiscus curtus, Lineus sp.), Annelida(Nereis pelagica, Pheretima tschiliensis), Mollusca (Cellana toreuma,Neverita didyma, Neptunea arthritica cumingi, Mactra chinensis, Mactra venerformis, Saxidomus purpuratus, Chlamys farreri, Dosinia japonica), Arthropoda(Squilla oratorio, Penaeus japonicus, Gaetice depressus, Portunus trituberculatus, Charybdis japoncia, Antheraea pernyi, Oxya chinensis, Oedaleus infernalis, Gastrimargus marmoratus, Haplotropis brunneriana). 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-dependent signalling pathways in different invertebrate species and general tendency in the evolution of NADPH-d-reactive cells in invertebrate is a migration of nitrergic function from periphery (Platyhelminthes and Nemertinea) to the centre nervous system (Arthropoda). (ii) There are more labeled central neurons in which lack special sense organ such as parasitism flatworm and Mactra chinensis, Mactra venerformis more than in which have developed sense organ as Nereis pelagica and Chlamys farreri. (iii)There are many labelled central neurons in predators (Neverita didyma, Neptunea arthritica cumingii, Squilla oratoria) and land animals (Pheretima tschiliensis and all tested insects) and many labelled peripheral putative sensory cells in herbivorous species (Cellana toreuma and most Bivalve).The distribution of 5-HT, Dopamine, Substance-P, CCK, SRIF, ACTH, nNOS, eNOS, and iNOS-containing cells has been analysed using immunohistochemistry in the centre nervous system and peripheral tissues in 6 invertebrates: Euplanaria gonocephala, Planocera reticulata, Cellana toreuma, Neverita didy...