Stress-induced release of octopamine in the American cockroach Periplaneta americana L

After stress, changes of octopamine content were observed in the antennal heart and the retrocerebral complex of cockroaches. Only individually handled animals exposed to short and extreme stress showed an alteration in the haemolymph octopamine levels. The removal of the retrocerebral complex resulted in an elevation of the octopamine content in the haemolymph. We suppose that the corpora cardiaca are not the only source for the octopamine released into haemolymph in stress situations.