This contraction is brought about by an integrated, cytoskeletal fiber system (myonemes and spasmoneme) that transverses from the oral opening, through the cell body and terminates at the end of the stalk (Amos 1972).
At the light microscopy level, two contractile organelles, the myonemes and spasmoneme, are detected by both antibodies (Fig.
Second, the peristomial ring formed by the myonemes does not fluoresce as strongly as with the N-termVcCentrin4-antibody.
One, [alpha]238305, is expressed near the pharynx, parietal muscle, and retractor muscle, suggesting a role in the adhesion of myonemes
to the extracellular matrix.
These impulses are heterogeneous in shape and probably arise either from neurons or myonemes; they are often likely to be a composite of both.
Biochemical studies have also indicated the presence of a receptor in membrane fractions of hydra that binds to the NMDA channel blocker, MK-801 (Pierobon et al., 2004a), and immunocytochemical studies provided evidence that NMDA receptors exist on the surface of nerve cells, nematocytes, myonemes of epitheliomuscular cells, and interstitial stem cells (Scappaticci et al., 2004).
Nerve processes from the gastrodermis crossed the muscle-free border of the mesoglea and entered into the individual oblong bundles of oral sphincter myonemes (Fig.
Most neurites observed within individual bundles of myonemes had densely granular vesicles, although occasional groups of nongranular vesicles were present.