Levels of tryptophan, 5-hydroxytryptamine, and dopamine in some tissues of the cockroach Periplaneta americana

Tryptophan, 5-hydroxytryptamine, and dopamine were measured in the frontal ganglion, corpora cardiaca, corpora allata, nerves of the suboesophageal ganglion, nerves of the thoracic ganglia, gut, testes, and ovaries of the cockroach Periplaneta americana using high performance liquid chromatography with electrochemical detection. 5-Hydroxytryptamine was demonstrated in the frontal ganglion, corpora cardiaca, corpora allata, and nerves of the suboesophageal ganglion but not in the gut, testes, ovaries, or nerves of the thoracic ganglia. These results quantitatively confirm immunohistochemical studies of 5-hydroxytryptamine in neurohaemal and nonneuronal tissues of the cockroach. Dopamine was found in all neurohaemal and nervous tissue examined. Dopamine was also found at low levels in the rectum. Tryptophan was found in all tissues examined.