Studies of the biogenic amine transporters 15. Identification of novel allosteric dopamine transporter ligands with nanomolar potency.
J Pharmacol Exp Ther
; 353(3): 529-38, 2015 Jun.
Article
em En
| MEDLINE
| ID: mdl-25788711
ABSTRACT
Novel allosteric modulators of the dopamine transporter (DAT) have been identified. We have shown previously that SRI-9804 [N-(diphenylmethyl)-2-phenyl-4-quinazolinamine], SRI-20040 [N-(2,2-diphenylethyl)-2-phenyl-4-quinazolinamine], and SRI-20041 [N-(3,3-diphenylpropyl)-2-phenyl-4-quinazolinamine] partially inhibit [(125)I]RTI-55 ([(125)I]3ß-(4'-iodophenyl)tropan-2ß-carboxylic acid methyl ester) binding and [(3)H]dopamine ([(3)H]DA) uptake, slow the dissociation rate of [(125)I]RTI-55 from the DAT, and allosterically modulate d-amphetamine-induced, DAT-mediated DA release. We synthesized and evaluated the activity of >500 analogs of these ligands and report here on 36 selected compounds. Using synaptosomes prepared from rat caudate, we conducted [(3)H]DA uptake inhibition assays, DAT binding assays with [(3)H]WIN35428 ([(3)H]2ß-carbomethoxy-3ß-(4-fluorophenyl)tropane), and DAT-mediated release assays with either [(3)H]MPP(+) ([(3)H]1-methyl-4-phenylpyridinium) or [(3)H]DA. We observed three groups of [(3)H]DA uptake inhibitors 1) full-efficacy agents with a one-site fit, 2) full-efficacy agents with a two-site fit, and 3) partial-efficacy agents with a one-site fit-the focus of further studies. These agents partially inhibited DA, serotonin, and norepinephrine uptake, yet were much less potent at inhibiting [(3)H]WIN35428 binding to the DAT. For example, SRI-29574 [N-(2,2-diphenylethyl)-2-(imidazo[1,2-a]pyridin-6-yl)quinazolin-4-amine] partially inhibited DAT uptake, with an IC50 = 2.3 ± 0.4 nM, without affecting binding to the DAT. These agents did not alter DAT-mediated release of [(3)H]MPP(+) in the absence or presence of 100 nM d-amphetamine. SRI-29574 had no significant effect on the d-amphetamine EC50 or Emax value for DAT-mediated release of [(3)H]MPP(+). These studies demonstrate the existence of potent DAT ligands that partially block [(3)H]DA uptake, without affecting DAT binding or d-amphetamine-induced [(3)H]MPP(+) release. These compounds may prove to be useful probes of biogenic amine transporter function as well as novel therapeutics.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas da Membrana Plasmática de Transporte de Dopamina
Tipo de estudo:
Diagnostic_studies
Limite:
Animals
Idioma:
En
Revista:
J Pharmacol Exp Ther
Ano de publicação:
2015
Tipo de documento:
Article