Cytomorphological aspects on the response of the branchial heart complex of Sepia officinalis L. (cephalopoda) to xenobiotics and bacterial infection.

The ovoid cells of the branchial heart complex of Sepia officinalis L. were investigated with respect to their role in detoxification processes. The electron microscopical localization of in situ injected ferritin in the endocytotic-lysosomal system, and the fluorescence microscopical localization of protein-bound Evans blue in the ovoid cells of in vivo incubated animals, indicate that foreign materials are eliminated from the hemolymph by the branchial heart tissue. In addition to the non-circulating ovoid cells of the branchial heart, hemocytes in the circulating blood and in the wall of the branchial heart are also involved in the incorporation of allogeneic substances and bacteria, or their debris. Based on these observations, we propose that the ovoid cells, together with circulating and adhesive hemocytes in the branchial hearts, are an important component of a more comprehensive defence and detoxification system in dibranchiate cephalopods that prevents contamination of the whole organism by endocytotic removal of noxious substances from the hemolymph.