Identification and Distribution of 5-Hydroxytryptamine in a Sea Anemone

Abstract

5-HYDROXYTRYPTAMINE is widely distributed in Nature and has been found in members of different groups, including vertebrates, molluscs and tunicates¹. It has also been detected in the venoms of Arthropoda, for example, wasps² and scorpions³. In plants, it has so far been identified in the dicotyledons cowhage⁴ and nettle⁵. In the present experiments we have identified 5-hydroxytryptamine in the tentacles, column (body wall), and in the structures of the cœlenteron (comprising mesenteries, gastric filaments, gonads, acontia, etc.) of the sea anemone Calliactis parasitica. The cœlenteric structures contained by far the highest concentration and the tentacles the least. In experiments on two different batches of Calliactis parasitica, the 5-hydroxytryptamine content of the cœlenteric tissues was 500 and 600 µgm./gm. freeze-dried tissue, whereas the tentacles of the same animals contained 7 and 6 µgm./gm. respectively (Table 1).