Allatostatin-like immunoreactivity in the abdomen of the locust Schistocerca gregaria

Petra Skiebe(1), Natalia M. Biserova(2), Varvara Vedenina(3), Jana Boerner(1), Hans-Joachim Pflueger(1)

(1)Institut fuer Biologie, Freie Universitaet Berlin, 14195 Berlin, Germany; (2)Department of Invertebrate Zoology, Moscow State University,119899, Moscow, Russia; (3)Institute of Problems in Information Transmission, Russian Academy of Science, 101447 Moscow, Russia

A polyclonal antibody against allatostatin 1 (AST-1) of cockroach Diploptera punctata was used to investigate the distribution of AST-like immunoreactivity within the abdomen of the locust, Schistocerca gregaria. In the abdominal ganglia, AST-like immunoreactivity was found in both cell bodies and neuropil. In the ganglia 6 and 7, staining was found in serial homologous cell bodies in anterior dorsolateral and dorsomedial, posterior ventrolateral and ventromedial locations. In the terminal ganglion, the numerous immunoreactive somata were smaller in size than those in the unfused ganglia. The combination of backfill experiments with immunocytochemistry showed that in abdominal ganglion 7 one neuron of the ventromedian cell body cluster and two of the ventrolateral cluster innervate the oviduct, which itself its covered with a dense mesh of AST-immunoreactive varicosities. Combining electron microscopy with immunohistochemistry showed that AST-like immunoreactivity is found in dense core vesicles located in neurohemal-like terminals which lack structures normally found in synapses. A mesh of AST-immunoreactive varicosities was also found on the muscles of the specmatheca and the spermathecal duct. In addition, a mesh of strongly stained varicosities was present in the distal perisympathetic organs, neurohemal organs in the abdomen, and on the lateral heart nerves which are a putative neurohemal release zone. These data indicate that AST seems to be an important neuroactive substance which is likely to be involved in multiple tasks in the control of the locust abdomen.