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Methyllycaconitine and (+)‐anatoxin‐a differentiate between nicotinic receptors in vertebrate and invertebrate nervous systems
Author(s) -
Macallan David R.E.,
Lunt George G.,
Wonnacott Susan,
Swanson Karen L.,
Rapoport Henry,
Albuquerque Edson X.
Publication year - 1988
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(88)81454-6
Subject(s) - methyllycaconitine , locust , nicotine , schistocerca , binding site , nicotinic agonist , receptor , acetylcholine receptor , chemistry , bungarotoxin , biology , pharmacology , biochemistry , nicotinic acetylcholine receptor , botany , neuroscience
Specific high‐affinity binding sites for 125 I‐α‐bungarotoxin and (−)‐[ 3 H]nicotine have been measured in rat brain and locust ( Schistocerca gregaria ) ganglia. The binding sites for 125 I‐α‐bungarotoxin had similar K d values of 1.5 × 10 −9 and 0.8 × 10 −9 M for rat and locust preparations, respectively; the corresponding values for the (−)‐[ 3 H]nicotine‐binding site were 9.3 × 10 −9 and 1.7 × 10 −7 M. Methyllycaconitine (MLA) potently inhibited 125 I‐α‐bungarotoxin binding in both rat and locust. MLA was a less effective inhibitor of (−)‐[ 3 H]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 α‐bungarotoxin.