التفاصيل البيبلوغرافية
| العنوان: |
Preclinical and clinical pharmacology of TPA023B, a GABAA receptor α2/α3 subtype-selective partial agonist. |
| المؤلفون: |
Atack JR, Hallett DJ, Tye S, Wafford KA, Ryan C, Sanabria-Bohórquez SM, Eng WS, Gibson RE, Burns HD, Dawson GR, Carling RW, Street LJ, Pike A, De Lepeleire I, Van Laere K, Bormans G, de Hoon JN, Van Hecken A, McKernan RM, Murphy MG |
| المصدر: |
Journal of Psychopharmacology; Mar2011, Vol. 25 Issue 3, p329-344, 16p |
| مستخلص: |
In the accompanying paper we describe how MRK-409 unexpectedly produced sedation in man at relatively low levels of GABA(A) receptor occupancy (∼10%). Since it was not clear whether this sedation was mediated via the α2/α3 or α1 GABA(A) subtype(s), we characterized the properties of TPA023B, a high-affinity imidazotriazine which, like MRK-409, has partial agonist efficacy at the α2 and α3 subtype but is an antagonist at the α1 subtype, at which MRK-409 has weak partial agonism. TPA023B gave dose- and time-dependent occupancy of rat brain GABA(A) receptors as measured using an in vivo [(3)H]flumazenil binding assay, with 50% occupancy corresponding to a respective dose and plasma drug concentration of 0.09 mg/kg and 19 ng/mL, the latter of which was similar to that observed in mice (25 ng/mL) and comparable to values obtained in baboon and man using [(11)C]flumazenil PET (10 and 5.8 ng/mL, respectively). TPA023B was anxiolytic in rodent and primate (squirrel monkey) models of anxiety (elevated plus maze, fear-potentiated startle, conditioned suppression of drinking, conditioned emotional response) yet had no significant effects in rodent or primate assays of ataxia and/or myorelaxation (rotarod, chain-pulling, lever pressing), up to doses (10 mg/kg) corresponding to occupancy of greater than 99%. In man, TPA023B was well tolerated at a dose (1.5 mg) that produced occupancy of >50%, suggesting that the sedation previously seen with MRK-409 is due to the partial agonist efficacy of that compound at the α1 subtype, and highlighting the importance of antagonist efficacy at this particular GABA(A) receptor population for avoiding sedation in man. [ABSTRACT FROM AUTHOR] |
|
Copyright of Journal of Psychopharmacology is the property of Sage Publications Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) |
| قاعدة البيانات: |
Complementary Index |
Full Text Finder