title: Neurotoxins distinguish between different neuronal nicotinic acetylcholine receptor subunit combinations.
abstract: Neuronal and muscle nicotinic acetylcholine receptor subunit combinations expressed in Xenopus oocytes were tested for sensitivity to various neurotoxins. Extensive blockade of the alpha 3 beta 2 neuronal subunit combination was achieved by 10 nM neuronal bungarotoxin. Partial blockade of the alpha 4 beta 2 neuronal and alpha 1 beta 1 gamma delta muscle subunit combinations was caused by 1,000 nM neuronal bungarotoxin. The alpha 2 beta 2 neuronal subunit combination was insensitive to 1,000 nM neuronal bungarotoxin. Nearly complete blockade of all neuronal subunit combinations resulted from incubation with 2 nM neosurugatoxin, whereas 200 nM neosurugatoxin was required for partial blockade of the alpha 1 beta 1 gamma delta muscle subunit combination. The alpha 2 beta 2 and alpha 3 beta 2 neuronal subunit combinations were partially blocked by 10,000 nM lophotoxin analog-1, whereas complete blockade of the alpha 4 beta 2 neuronal and alpha 1 beta 1 gamma delta muscle subunit combinations resulted from incubation with this concentration of lophotoxin analog-1. The alpha 1 beta 1 gamma delta muscle subunit combination was blocked by the alpha-conotoxins G1A and M1 at concentrations of 100 nM. All of the neuronal subunit combinations were insensitive to 10,000 nM of both alpha-conotoxins. Thus, neosurugatoxin and the alpha-conotoxins distinguish between muscle and neuronal subunit combinations, whereas neuronal bungarotoxin and lophotoxin analog-1 distinguish between different neuronal subunit combinations on the basis of differing alpha subunits.
authors.affiliation: Division of Neuroscience, Baylor College of Medicine, Houston, Texas 77030.
authors.forename: C W
authors.initials: CW
authors.lastname: Luetje
authors.forename: K
authors.initials: K
authors.lastname: Wada
authors.forename: S
authors.initials: S
authors.lastname: Rogers
authors.forename: S N
authors.initials: SN
authors.lastname: Abramson
authors.forename: K
authors.initials: K
authors.lastname: Tsuji
authors.forename: S
authors.initials: S
authors.lastname: Heinemann
authors.forename: J
authors.initials: J
authors.lastname: Patrick
mesh_terms: D000818:Animals; D002038:Bungarotoxins / Q000494:pharmacology; D003064:Cnidarian Venoms / Q000494:pharmacology; D020916:Conotoxins; D005260:Female; D015870:Gene Expression; D046911:Macromolecular Substances; D008978:Mollusk Venoms / Q000494:pharmacology; D009474:Neurons / Q000032:analysis*; D009498:Neurotoxins / Q000494:pharmacology*; D009865:Oocytes / Q000378:metabolism; D010456:Peptides, Cyclic / Q000494:pharmacology; D011978:Receptors, Nicotinic / Q000235:genetics / Q000378:metabolism*; D013729:Terpenes; D014162:Transfection; D014982:Xenopus laevis
chemical_list: D002038:Bungarotoxins; D003064:Cnidarian Venoms; D020916:Conotoxins; D046911:Macromolecular Substances; D008978:Mollusk Venoms; D009498:Neurotoxins; D010456:Peptides, Cyclic; D011978:Receptors, Nicotinic; D013729:Terpenes; C030303:lophotoxin; C029960:conotoxin GI; C036793:neosurugatoxin; C036155:conotoxin MI