NEOSURUGATOXIN BLOCKS AN ALPHA-BUNGAROTOXIN-SENSITIVE NEURONAL NICOTINIC ACETYLCHOLINE-RECEPTOR

Neosurugatoxin (NSTX), a neurotoxin isolated from the Japanese ivory m ollusc Babylonia japonica, is a potent neuronal nicotinic acetylcholin e receptor (nAChR) antagonist. Hitherto, NSTX has been found to block only neuronal nAChRs that are insensitive to alpha-Bgt. Here, we repor t for the first time that NSTX blocks an alpha-Bgt-sensitive nAChR on an identified insect motor neurone. Bath-applied NSTX at a concentrati on of 10 nM and above reversibly blocks the nicotine-induced depolariz ations recorded from the cockroach (Periplaneta americana) fast coxal depressor motor neurone (D(f)) and is without effect on GABA-induced r esponses detected on the same cell. NSTX is among the most potent bloc kers tested to date on nAChRs of motor neurone D(f). (C) 1993 Wiley-Li ss, Inc.