Novel N-substituted 3 alpha-[bis(4'-fluorophenyl)methoxy]tropane analogues: selective ligands for the dopamine transporter.
A series of N-substituted 3 alpha-[bis(4'-fluorophenyl)methoxy]tropane analogues has been prepared that function as dopamine uptake inhibitors. The N-methylated analogue of this series had a significantly higher affinity for the dopamine transporter than the parent compound, N-methyl-3 alpha- (diphenylmethoxy)tropane (benztropine, Cogentin). Yet like the parent compound, it retained high affinity for muscarinic receptors. A series of N-substituted compounds were prepared from nor-3 alpha-[bis(4'-fluorophenyl)methoxy]tropane via acylation followed by hydride reduction of the amide or by direct alkylation. All compounds containing a basic tropane nitrogen displaced [3H]WIN 35,428 at the dopamine transporter (Ki range = 8.5-634 nM) and blocked dopamine uptake (IC50 range = 10-371 nM) in rat caudate putamen, whereas ligands with a nonbasic nitrogen were virtually inactive. None of the compounds demonstrated high binding affinity at norepinephrine or serotonin transporters. Importantly, a separation of binding affinities for the dopamine transporter versus muscarinic m1 receptors was achieved by substitution of the N-methyl group with other N-alkyl or arylalkyl substituents (eg. n-butyl, allyl, benzyl, 3-phenylpropyl, etc.). Additionally, the most potent and selective analogue in this series at the dopamine transporter, N-(4"-phenyl-n-butyl)-3 alpha-[bis(4'-fluorophenyl)methoxy]tropane analogue failed to substitute for cocaine in rats trained to discriminate cocaine from saline. Potentially, new leads toward the development of a pharmacotherapeutic for cocaine abuse and other disorders affecting the dopamine transporter may be discovered.
Agoston
G E
GE
Psychobiology Section, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland 21224, USA.
Wu
J H
JH
Izenwasser
S
S
George
C
C
Katz
J
J
Kline
R H
RH
Newman
A H
AH
D000818:Animals; D001667:Binding, Competitive; D001921:Brain / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D003042:Cocaine / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D018360:Crystallography, X-Ray; D004298:Dopamine / Q000378:metabolism; D050483:Dopamine Plasma Membrane Transport Proteins; D018765:Dopamine Uptake Inhibitors / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D008024:Ligands; D008297:Male; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D051379:Mice; D008958:Models, Molecular; D015394:Molecular Structure; D009043:Motor Activity / Q000187:drug effects; D009419:Nerve Tissue Proteins; D051381:Rats; D011976:Receptors, Muscarinic / Q000378:metabolism; D013329:Structure-Activity Relationship; D014326:Tropanes / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology
D002352:Carrier Proteins; D050483:Dopamine Plasma Membrane Transport Proteins; D018765:Dopamine Uptake Inhibitors; D008024:Ligands; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D011976:Receptors, Muscarinic; D014326:Tropanes; C021279:(1R-(exo,exo))-3-(4-fluorophenyl)-8-methyl-8- azabicyclo(3.2.1)octane-2-carboxylic acid, methyl ester; D003042:Cocaine; D004298:Dopamine