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Jucaite A, Cselényi Z, Lappalainen J, McCarthy DJ, Lee CM, Nyberg S, Varnäs K, Stenkrona P, Halldin C, Cross A, Farde L. GABA A receptor occupancy by subtype selective GABA Aα2,3 modulators: PET studies in humans. Psychopharmacology (Berl) 2017; 234:707-716. [PMID: 28013354 PMCID: PMC5263201 DOI: 10.1007/s00213-016-4506-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 12/08/2016] [Indexed: 01/04/2023]
Abstract
RATIONALE Sedation, dependence, and abuse liability limit the use of non-selective γ-aminobutyric acid (GABAA) receptor positive modulators for the treatment of anxiety. AZD7325 and AZD6280 are novel, subtype-selective GABAAα2,3 receptor positive modulators with limited sedative effects. OBJECTIVES The current study aimed to confirm target engagement at GABAA receptors by AZD7325 and AZD6280 in humans and to determine the relationship between exposure, GABAA receptor occupancy, and tolerability. METHOD Two PET studies, using high-resolution research tomography (HRRT) and the radioligand [11C]flumazenil, were performed in 12 subjects at baseline and after administration of single oral doses of AZD7325 (0.2 to 30 mg) and AZD6280 (5 to 40 mg). PET images were analyzed using a simplified reference tissue model, and regional binding potentials (BPND) were obtained. The relationship between plasma concentration of AZD7325 or AZD6280 and GABAA receptor occupancy was described by hyperbolic function, and K i,plasma (plasma concentration required for 50% receptor occupancy) was estimated. Assessments of safety and tolerability included recording of adverse events, vital signs, electrocardiogram, and laboratory tests. RESULTS The [11C]flumazenil binding was reduced in a dose-dependent, saturable manner by both agents. Maximum receptor occupancy could be reached for both compounds without causing sedation or cognitive impairment. The K i,plasma estimates for AZD7325 and AZD6280 were 15 and 440 nmol/l, respectively. CONCLUSION High GABAA receptor occupancy by AZD7325 and AZD6280 could be reached without clear sedative effects.
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Affiliation(s)
- Aurelija Jucaite
- Department of Clinical Neuroscience, AstraZeneca PET Center, Karolinska Institutet, R5:02, SE-17176, Stockholm, Sweden. .,Department of Clinical Neuroscience, PET Centre, Karolinska Institutet, Stockholm, Sweden.
| | - Zsolt Cselényi
- 0000 0004 1937 0626grid.4714.6Department of Clinical Neuroscience, AstraZeneca PET Center, Karolinska Institutet, R5:02, SE-17176 Stockholm, Sweden ,0000 0004 1937 0626grid.4714.6Department of Clinical Neuroscience, PET Centre, Karolinska Institutet, Stockholm, Sweden
| | - Jaakko Lappalainen
- AstraZeneca Neuroscience Innovative Medicines, Cambridge, MA USA ,Marinus Pharmaceuticals, Radnor, PA USA
| | - Dennis J. McCarthy
- 0000 0001 1519 6403grid.418151.8AstraZeneca R&D, Södertälje, Sweden ,Independent Consultant, Newark, DE USA
| | - Chi-Ming Lee
- 0000 0001 1519 6403grid.418151.8AstraZeneca R&D, Södertälje, Sweden ,Ever East Consultants Limited, Hong Kong, People’s Republic of China
| | - Svante Nyberg
- 0000 0001 1519 6403grid.418151.8AstraZeneca R&D, Södertälje, Sweden ,0000 0000 9241 5705grid.24381.3cDepartment of Psychiatry, Karolinska University Hospital (Huddinge), Stockholm, Sweden
| | - Katarina Varnäs
- 0000 0004 1937 0626grid.4714.6Department of Clinical Neuroscience, PET Centre, Karolinska Institutet, Stockholm, Sweden
| | - Per Stenkrona
- 0000 0004 1937 0626grid.4714.6Department of Clinical Neuroscience, PET Centre, Karolinska Institutet, Stockholm, Sweden
| | - Christer Halldin
- 0000 0004 1937 0626grid.4714.6Department of Clinical Neuroscience, PET Centre, Karolinska Institutet, Stockholm, Sweden
| | - Alan Cross
- AstraZeneca Neuroscience Innovative Medicines, Cambridge, MA USA
| | - Lars Farde
- 0000 0004 1937 0626grid.4714.6Department of Clinical Neuroscience, AstraZeneca PET Center, Karolinska Institutet, R5:02, SE-17176 Stockholm, Sweden ,0000 0004 1937 0626grid.4714.6Department of Clinical Neuroscience, PET Centre, Karolinska Institutet, Stockholm, Sweden
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