Cholinergic components of the nervous system of the digenean parasites, Haplorchoides cahirinus and Acanthostomum absconditum from the catfish Bagrus bayad in Egypt

A comparison has been made for the first time between the cholinergic components of the nervous system of the intestinal digeneans, Acanthostomum absconditum and Haplorchoides cahirinus from catfish, Bagrus bayad caught in Egypt. Some important differences in the central and the peripheral nervous systems are recorded between the two digeneans. The number of transverse connectives in A. absconditum is greater than in H. cahirinus, while the number of ring commissures in H. cahirinus (10) is greater in A. absconditum (3). Innervation of the subtegumental muscles, anal opening, excretory pores and ootype are revealed only in A. absconditum. Many cholinergic bipolar and multipolar nerve cell bodies (somata) are evident in A. absconditum. These cells lie close to the dorsal surface and are associated with the dorsal nerve cords and nerves supplying the subtegumental muscles. Possible functions of some nervous components are discussed.