ACTIONS OF A CORAL TOXIN ANALOG (BIPINNATIN-B) ON AN INSECT NICOTINIC ACETYLCHOLINE-RECEPTOR

The lophotoxin analogue, bipinnatin-B, is a potent neurotoxin isolated from the gorgonian coral Pseudopterogorgia bipinnata. When tested on the cell body of an identified motor neurone, the fast coxal depressor motor neurone (D(f)) in the cockroach metathoracic ganglion, bipinnatin-B, at concentrations of 10 muM, partially blocked nicotine-induced depolarization. Blockade of the response to nicotine was almost complete at 30 muM bipinnatin-B, and was partially reversible on rebathing the preparation in normal saline. Responses of the same neurone to GABA were unaffected by 30 muM bipinnatin-B. (C) 1993 Wiley-Liss, Inc.