title: Methyllycaconitine and (+)-anatoxin-a differentiate between nicotinic receptors in vertebrate and invertebrate nervous systems.
abstract: Specific high-affinity binding sites for 125I-alpha-bungarotoxin and (-)-[3H]nicotine have been measured in rat brain and locust (Schistocerca gregaria) ganglia. The binding sites for 125I-alpha-bungarotoxin had similar Kd values of 1.5 x 10(-9) and 0.8 x 10(-9) M for rat and locust preparations, respectively; the corresponding values for the (-)-[3H]nicotine-binding site were 9.3 x 10(-9) and 1.7 x 10(-7) M. Methyllycaconitine (MLA) potently inhibited 125I-alpha-bungarotoxin binding in both rat and locust. MLA was a less effective inhibitor of (-)-[3H]nicotine binding whereas (+)-anatoxin-a was a very potent inhibitor at this site in the rat but not in the locust. These data suggest that (+)-anatoxin-a is a useful probe for the high-affinity nicotine-binding receptor in vertebrate brain, whereas MLA is a preferential probe for the subclass of receptor that binds alpha-bungarotoxin.
authors.affiliation: Department of Biochemistry, University of Bath, England.
authors.forename: D R
authors.initials: DR
authors.lastname: Macallan
authors.forename: G G
authors.initials: GG
authors.lastname: Lunt
authors.forename: S
authors.initials: S
authors.lastname: Wonnacott
authors.forename: K L
authors.initials: KL
authors.lastname: Swanson
authors.forename: H
authors.initials: H
authors.lastname: Rapoport
authors.forename: E X
authors.initials: EX
authors.lastname: Albuquerque
mesh_terms: D000157:Aconitine / Q000031:analogs & derivatives* / Q000494:pharmacology; D031841:Aconitum / Q000031:analogs & derivatives*; D000818:Animals; D001427:Bacterial Toxins; D001667:Binding, Competitive; D001921:Brain / Q000378:metabolism*; D002038:Bungarotoxins / Q000378:metabolism; D000087522:Cyanobacteria Toxins; D005724:Ganglia / Q000378:metabolism; D006110:Grasshoppers / Q000378:metabolism*; D007700:Kinetics; D008387:Marine Toxins / Q000494:pharmacology*; D052998:Microcystins; D009538:Nicotine / Q000378:metabolism; D051381:Rats; D011978:Receptors, Nicotinic / Q000187:drug effects / Q000378:metabolism*; D013045:Species Specificity; D014326:Tropanes
chemical_list: D001427:Bacterial Toxins; D002038:Bungarotoxins; D000087522:Cyanobacteria Toxins; D008387:Marine Toxins; D052998:Microcystins; D011978:Receptors, Nicotinic; D014326:Tropanes; C054634:methyllycaconitine; D009538:Nicotine; C509783:anatoxin a; D000157:Aconitine