title: Neosurugatoxin, a specific antagonist of nicotinic acetylcholine receptors.
abstract: Neosurugatoxin (NSTX) (3 nM-30 nM), recently isolated from the Japanese ivory mollusc (Babylonia japonica) exerted a potent antinicotinic action in the isolated guinea pig ileum. Specific [3H]nicotine binding to rat forebrain membranes was saturable, reversible, and of high affinity. Nicotinic cholinergic agonists exhibited a markedly greater affinity for [3H]nicotine binding sites than a muscarinic agonist, oxotremorine. Although alpha-bungarotoxin had no effect on [3H]nicotine binding, low concentrations (1 nM-1 microM) of NSTX inhibited [3H]nicotine binding in the forebrain membranes and its IC50 value was 69 +/- 6 nM. On the other hand, NSTX did not affect muscarinic receptor binding in the brain. These data indicate that NSTX may be of appreciable interest as a neurotoxin with a selective affinity for ganglionic nicotinic receptors.
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D001921:Brain / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects; D007700:Kinetics; D008297:Male; D008387:Marine Toxins / Q000494:pharmacology*; D008978:Mollusk Venoms; D009119:Muscle Contraction / Q000187:drug effects; D009538:Nicotine / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011978:Receptors, Nicotinic / Q000187:drug effects* / Q000378:metabolism
chemical_list: D008387:Marine Toxins; D008978:Mollusk Venoms; D011978:Receptors, Nicotinic; D009538:Nicotine; C036793:neosurugatoxin