Immunohistochemical characterization of a widely spread Arg8-vasopressin-like neuroendocrine system in the cricket Teleogryllus commodus Walker (Orthoptera, Insecta).

Two distinct neurons located paramedially within the suboesophageal ganglion of female Australian crickets Teleogryllus commodus were shown to contain Arg8-vasopressin-like immunoreactivity. Immunostained processes project throughout the ganglion. They pass the circumoesophageal connectives, and finally they branch out and enter the neurohemal region of the deuterocerebrum. By means of radioimmunoassay in homogenized cricket brains and suboesophageal ganglia evidence could be found for the presence of a neurohypophyseal-peptide-like substance. Immunofluorescence findings indicate that immunoreactive axonal tracts extend backwards through the ventral nerve cord to the terminal ganglion. Numerous beaded axons with specific immunostaining were also detected within the lateral nerves.