Actinlike filaments in the neurosecretory cells of Helisoma duryi (Gastropoda, Pulmonata)

Abstract

The mediodorsal neurosecretory cells in the cerebral ganglia of Helisoma duryi send axons into the median lip nerve, where they terminate to form a probable neurohaemal area. After glycerination these cells are shown to contain a branching network of 5- to 6-nm diameter filaments, which are abundant throughout the axon and axon ending but less prominent in the perikaryon. The filaments react with heavy meromyosin subfraction SI, increasing in thickness and forming arrowhead-shaped complexes; the reaction is reversed by adenosine 5′-triphosphate (ATP). This reaction indicates that the filaments contain actin, and it is suggested that actin–myosin interactions could be responsible for neurosecretory granule transport along the axon.

Cercaria vaullegeardi Pelseneer, 1906 (Digenea: Hemiuridae); development and ultrastructure

“…The absence of muscle fibres need not necessarily, however, rule out an active process, as contraction could be a function of the fibrous layer. The occurrence of contractile properties in many types of non-muscle cell is well documented (Allison, Davies & dePetris, 1971;Bettex-Galland & Hughes, 1973;Bray, 1973;Pollard & Korn, 1973;Schliwa & Bereiter-Hahn, 1975;Saleuddin & Jones, 1976).…”

The effects of mating on the fine structure of neurosecretory caudodorsal cells in Helisoma duryi (Mollusca)

“…The location of these cells in Helisoma is in the mid-anterior portion of the cerebral ganglia, and their neurohaemal area is the median lip nerve; the granules of these cells are uniform in size, spherical, and electron dense (Saleuddin and Jones 1976). Since the enclosing membrane of the MDC granules is somewhat undulating, they can be easily distinguished from the CDC granules.…”