Interactions of the echinoderm toxin holothurin a and its desulfated derivative with the cat superior cervical ganglion preparation

Abstract

Purified samples of the toxin Holothurin A (H −) elaborated by the sea cucumber Actinopyga agassizi, Selenka and of its neutral desulfated derivative (DeH) were studied for actions on the cat superior cervical ganglion preparation. It was observed that each saponin produces irreversible inactivation of the ganglion on injection into its bathing circulation, and that the charged anion H − is about one order of magnitude more potent in this regard than its neutral congener DeH. However, at levels (≤5 × 10 −3 M) below its own effective blockade concentration, DeH is able to extend markedly the survival of ganglionic excita- bility against the rapid destruction normally wrought by 1 × 10 −3 M injections of H −. Mechanisms for toxin-receptor interactions leading to H − destruction of excitability and to the partial protection afforded by DeH are briefly discussed.