[N-methyl-3H3]AZ10419369 Binding to the 5-HT1BReceptor: In Vitro Characterization and in Vivo Receptor Occupancy
| Autor: | J. Richard Heys, Donna L. Maier, Mark E. Powell, Charles S. Elmore, Cindy Sobotka-Briner, Min Ding, Qiaoling Jiang, M. Edward Pierson, Geraldine Hill, Ladislav Mrzljak |
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| Rok vydání: | 2009 |
| Předmět: |
Male
Morpholines Guinea Pigs CHO Cells Striatum Serotonin 5-HT1 Receptor Antagonists Pharmacology Biology Tritium Piperazines Cell Line Guinea pig Cricetulus In vivo Cricetinae Animals Humans Benzopyrans Receptor Chinese hamster ovary cell Haplorhini In vitro Globus pallidus Receptor Serotonin 5-HT1B Molecular Medicine Serotonin Antagonists Serotonin Radiopharmaceuticals Protein Binding |
| Zdroj: | Journal of Pharmacology and Experimental Therapeutics. 330:342-351 |
| ISSN: | 1521-0103 0022-3565 |
| Popis: | Radiotracers suitable for positron emission tomography studies often serve as preclinical tools for in vivo receptor occupancy. The serotonin 1B receptor (5-HT(1B)) subtype is a pharmacological target used to discover treatments for various psychiatric and neurological disorders. In psychiatry, 5-HT(1B) antagonists may provide novel therapeutics for depression and anxiety. We report on the in vitro and in vivo evaluation of tritiated 5-methyl-8-(4-methyl-piperazin-1-yl)-4-oxo-4H-chromene-2-carboxylicacid (4-morpholin-4-yl-phenyl)-amide ([N-methyl-(3)H(3)]AZ10419369), a potent 5-HT(1B) radiotracer. [N-methyl-(3)H(3)]-AZ10419369 showed saturable single-site high-affinity in vitro binding (guinea pig, K(d) = 0.38 and human, K(d) = 0.37) to guinea pig or human 5-HT(1B) receptors in recombinant membranes and high-affinity (K(d) = 1.9 nM) saturable (B(max) = 0.099 pmol/mg protein) binding in membranes from guinea pig striatum. When [N-methyl-(3)H(3)]AZ10419369 was administered to guinea pigs by intravenous bolus, the measured radioactivity was up to 5-fold higher in brain areas containing the 5-HT(1B) receptor (striatum/globus pallidus, midbrain, hypothalamus, and frontal cortex) compared with the cerebellum, the nonspecific binding region. Specific uptake peaked 30 min after injection with slow dissociation from target regions, as suggested by the in vitro binding kinetic profile. Pretreatment with 6-fluoro-8-(4-methyl-piperazin-1-yl)-4-oxo-4H-chromene-2-carboxylic acid [4-(4-propionyl-piperazin-1-yl)-phenyl]-amide (AZD1134) and 2-aminotetralin (AR-A000002), 5-HT(1B)-selective ligands, inhibited [N-methyl-(3)H(3)]AZ10419369-specific binding in a dose-dependent manner. In the guinea pig striatum, AZD1134 (ED(50) = 0.017 mg/kg) occupies a greater percentage of the 5-HT(1B) receptors at a lower administered dose than AR-A000002 (ED(50) = 2.5 mg/kg). In vivo receptor occupancy is an essential component to build binding-efficacy-exposure relationships and compare novel compound pharmacology. [N-methyl-(3)H(3)]AZ10419369 is a useful preclinical tool for investigating 5-HT(1B) receptor occupancy for novel compounds targeting this receptor. |
| Databáze: | OpenAIRE |
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