Binding differences between nicotine and alpha-bungarotoxin in the rat brain
Nukina, I.; Ogawa, N.; Takayama, H.; Ota, Z.
Research Communications in Chemical Pathology and Pharmacology 47(1): 141-144
1985
ISSN/ISBN: 0034-5164 PMID: 2858912 Document Number: 243605
Radioreceptor assay (RAA) results in rat brain with 3H-nicotine were compared with those obtained using 125I-alpha-Bungarotoxin (BTX). Scatchard analysis showed that the 3H-nicotine binding site had an average Kd and Bmax of 5.31 nM and 0.047 p moles/mg protein, respectively, and that the corresponding 125I-alpha-BTX binding site values were 0.092 nM and 0.044 p moles/mg protein. Cotinine, which is a nicotine metabolite and has a nicotine-like effect in vivo, inhibited 3H-nicotine binding but did not inhibit 125I-alpha-BTX binding. This result suggests that 3H-nicotine is a more useful ligand than 125I-alpha-BTX for investigating the pharmacological action of nicotine in the brain.