Cockroach allatostatin-like immunoreactivity in the synganglion of the American dog tick Dermacentor variabilis (Acari: Ixodidae).

Using immunocytochemistry based on a monoclonal antibody against Diploptera punctata allatostatin I and horseradish peroxidase-diaminobenzidine reaction, the presence of allatostatin-like immunoreactivity is demonstrated in the synganglion of Dermacentor variabilis females. The immunoreactive cells are located in the protocerebral, cheliceral, palpal, stomodeal, postesophageal, and opisthosomal regions of the synganglion. Strongly immunoreactive granules accumulate in the boundary area of the subganglia in the preesophageal part of the synganglion. This suggests that the immunoreactive materials may be released directly from there. In addition, a putative neurohemal area is found in the anterior area of the opisthosomal ganglion, where abundant immunoreactive materials are stored. Weak immunoreactivity and fewer immunoreactive cells are seen in newly molted females compared with one month old, unfed females. Thus, the immunoreactive products may be depleted during molting and synthesized in females before feeding.