Binding characteristics of (-)- and (+)-nicotine to the rat brain P2 fraction.
Saturation studies employing (-)- and (+)-[3H]nicotine indicate that the isomers bind to different very high and high affinity sites since the binding density for (-)-[3H]nicotine is 10 times that for (+)-[3H]nicotine. Both isomers also bind to a low affinity site (KDS = approximately 10(-5) to 10(-4) M). Competition studies employing unlabelled (-)- and (+)-nicotine reveal greater complexities. The isomers also appear to bind to a separate site which enhances binding at the (-)- and (+)-nicotine high affinity sites. (+)-Nicotine is more effective in increasing the binding of (-)-[3H]nicotine at its high affinity site than (-)-nicotine. Further, (+)-nicotine has a greater specificity for enhancing binding than (-)-nicotine in that it enhances (-)-[3H]nicotine binding at lower concentrations and inhibits binding at higher concentrations than (-)-nicotine.
D000818:Animals; D001921:Brain / Q000378:metabolism*; D055598:Chemical Phenomena; D002621:Chemistry; D005260:Female; D066298:In Vitro Techniques; D007700:Kinetics; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009538:Nicotine / Q000378:metabolism*; D051381:Rats; D011978:Receptors, Nicotinic / Q000378:metabolism; D013237:Stereoisomerism
D009419:Nerve Tissue Proteins; D011978:Receptors, Nicotinic; D009538:Nicotine