EFFECTS OF SEA-ANEMONE (HETERACTIS-MAGNIFICA AND ACTINIA-EQUINA) CYTOLYSINS ON SYNAPTOSOMAL UPTAKE OF GABA AND CHOLINE

Magnificalysin I and II (HMg I and II) and equinatoxin II (EqTx II) ar e cytolytic toxins extracted from sea anemones Heteractis magnifica an d Actinia equina, respectively. They induced haemolysis in rat red blo od cells and inhibited gamma amino butyric acid (GABA) and choline upt ake into rat brain synaptosomes. These effects were concentration depe ndent. The inhibition of GABA and choline uptake could be overcome by the addition of exogeneous sphingomyelin, suggesting that there might be interaction between these cytolysins and the phospholipid. Although the precise mechanisms involved in haemolysis and inhibition of GABA and choline uptake are unknown, they appeared to be different.