The octopaminergic system within the ventral nerve cord of the American cockroach

Octopamine-immunoreactive neurons within the ventral nerve cord of the cockroach, Periplaneta americana, were mapped with a new anti-octopamine serum. The specificity of this antiserum was demonstrated by dot blot immunoassay and by comparing the immunocytochemical staining patterns obtained after incubation with anti-dopamine and anti-octopamine serum. Putative octopaminergic dorsal and ventral unpaired median (DUM resp. VUM) neurons showed octopamine-like immunoreactivity in all ventral ganglia. The numbers of DUM cells in the mesothoracic, metathoracic and terminal ganglia of females correspond to those previously characterized by retrograde staining 19, 33, 34. It could be shown that besides segmentally projecting there are also intersegmentally projecting DUM neurons within the thoracic ganglia. In addition various, previously unknown, paired octopamine-ir cells were revealed in all ventral ganglia except the abdominal ganglia 2-5.