Methyllycaconitine and (+)-anatoxin-a differentiate between nicotinic receptors in vertebrate and invertebrate nervous systems.
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.
Macallan
D R
DR
Department of Biochemistry, University of Bath, England.
Lunt
G G
GG
Wonnacott
S
S
Swanson
K L
KL
Rapoport
H
H
Albuquerque
E X
EX
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
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