CHOLINERGIC, SEROTONINERGIC AND PEPTIDERGIC COMPONENTS OF THE NERVOUS-SYSTEM OF DISCOCOTYLE SAGITTATA (MONOGENEA, POLYOPISTHOCOTYLEA)

Cholinergic, serotoninergic (5-HT) and peptidergic neuronal pathways h ave been demonstrated in both central and peripheral nervous systems o f adult Discocotyle sagittata, using enzyme histochemistry and indirec t immunocytochemistry in conjunction with confocal scanning laser micr oscopy. Antisera to 2 native flatworm neuropeptides, neuropeptide F an d the fMRFamide-related peptide (FaRP), GNFFRFamide, were employed to detect peptide immunoreactivity. The CNS is composed of paired cerebra l ganglia and connecting dorsal commissure, together with several pair ed longitudinal nerve cords. The main longitudinal nerve cords (latera l, ventral and dorsal) are interconnected at intervals by a series of annular cross-connectives, producing a ladder-like arrangement typical of the platyhelminth nervous system. At the lever of the haptor, the ventral cords provide nerve roots which innervate each of the 8 clamps . Cholinergic and peptidergic neuronal organisation was similar, but d istinct from that of the serotoninergic components. The PNS and reprod uctive system are predominantly innervated by peptidergic neurones. Co pyright (C) 1996 Australian Society for Parasitology. Published by Els evier Science Ltd.