Studies on the Structure and Function of the Salivary Gland of the Tick Amblyomma Variegatum (Fabricius, 1794)

Abstract

Using electron microscopy and various histochemical techniques, it was possible to distinguish about 9 different secretory cells ('a' cells, 'b' cells and 5 types of 'c' cells) in the type II acini in the salivary gland of females of Amblyomma variegatum, and 3 ('d', 'e' and 'f' cells) in the type III acini. The 'a' and 'd' cells stained strongly for esterases, whereas the 'c' cells stained strongly for the presence of glycoproteins. Dopamine and pilocarpine were used to stimulate salivation. Electrophoretic analysis of the saliva indicated that certain products identified by histochemical means in the salivary gland were excreted and passed to the host. Analysis of tick saliva was suggested as a useful technique for identifying the antigens involved in host resistance to tick infestation. It was also found that the ratio of the cube root of tick weight to the square root of the surface area of the scutum was a good measure of engorgement.