Fig. 7

a Within the acanthocephalan infected intestines of Squalius cephalus, the goblets of the mucous cells in the intestinal epithelium are shown to be immunofluroreactive to DBA (left image), while the endocrine cells are seen to be immmunofluroreactive to the met-enkephalin antiserum (middle image). Note the “reservoir-like” shape of the endocrine cells (arrowhead) and the close contact between a mucous cell and an endocrine cell (thin arrow, right image). b Mucous cells that are immunofluororeactive to the DBA lectin (left image). The middle image shows three endocrine cells, in a section taken from the intestine of an infected host, that are immunofluororeactive to the serotonin antiserum. The cytoplasmic processes of the immunofluororeactive endocrine cells appear to envelope the cytoplasm of the mucous cells (thin arrow, right image). c The apical portion of an endocrine cell that possesses a mid-epithelial body that is immunofluororeactive to the met-enkephalin antiserum; this cell is close to the apical goblet of a mucous cell. d An endocrine cell with a “reservoir-like” appearance within the gut epithelium of an infected host that is immunofluoropositive to the serotonin antiserum. Scale bars 20 μm