Identification of a novel, selective GABA(A) alpha5 receptor inverse agonist which enhances cognition.
In pursuit of a GABA(A) alpha5-subtype-selective inverse agonist to enhance cognition, a series of 6,7-dihydro-2-benzothiophen-4(5H)-ones has been identified as a novel class of GABA(A) receptor ligands. These thiophenes have higher binding affinity for the GABA(A) alpha5 receptor subtype compared to the GABA(A) alpha1, alpha2, and alpha3 subtypes, and several analogues exhibit high GABA(A) alpha5 receptor inverse agonism. 6,6-Dimethyl-3-(2-hydroxyethyl)thio-1-(thiazol-2-yl)-6,7-dihydro-2-benzothiophen-4(5H)-one (43) has been identified as a full inverse agonist at the GABA(A) alpha5 receptor and is functionally selective over the other major GABA(A) receptor subtypes. 43 readily penetrates into the CNS to give selective occupancy of GABA(A) alpha5 receptors. In addition, 43 enhances cognitive performance in rats in the delayed 'matching-to-place' Morris water maze test-a hippocampal-dependent memory task-without the convulsant or proconvulsant activity associated with nonselective, GABA(A) receptor inverse agonists.
Chambers
Mark S
MS
Merck Sharp & Dohme Research Laboratories, The Neuroscience Research Centre, Terlings Park, Eastwick Road, Harlow, Essex, CM20 2QR, UK. mark_chambers@merck.com
Atack
John R
JR
Broughton
Howard B
HB
Collinson
Neil
N
Cook
Susan
S
Dawson
Gerard R
GR
Hobbs
Sarah C
SC
Marshall
George
G
Maubach
Karen A
KA
Pillai
Goplan V
GV
Reeve
Austin J
AJ
MacLeod
Angus M
AM
D000818:Animals; D001921:Brain / Q000378:metabolism; D002460:Cell Line; D003071:Cognition / Q000187:drug effects*; D005260:Female; D018755:GABA Agonists / Q000009:adverse effects / Q000138:chemical synthesis* / Q000494:pharmacology; D006624:Hippocampus / Q000502:physiology; D006801:Humans; D066298:In Vitro Techniques; D008024:Ligands; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D008568:Memory / Q000187:drug effects; D051379:Mice; D018697:Nootropic Agents / Q000009:adverse effects / Q000138:chemical synthesis* / Q000494:pharmacology; D009865:Oocytes / Q000187:drug effects / Q000502:physiology; D018408:Patch-Clamp Techniques; D021122:Protein Subunits; D011869:Radioligand Assay; D051381:Rats; D011963:Receptors, GABA-A / Q000187:drug effects*; D012640:Seizures / Q000139:chemically induced; D013329:Structure-Activity Relationship; D013844:Thiazoles / Q000009:adverse effects / Q000138:chemical synthesis* / Q000494:pharmacology; D013876:Thiophenes / Q000009:adverse effects / Q000138:chemical synthesis* / Q000494:pharmacology; D014982:Xenopus laevis
C452421:6,6-dimethyl-3-(2-hydroxyethyl)thio-1-(thiazol-2-yl)-6,7-dihydro-2-benzothiophen-4(5H)-one; D018755:GABA Agonists; D008024:Ligands; D018697:Nootropic Agents; D021122:Protein Subunits; D011963:Receptors, GABA-A; D013844:Thiazoles; D013876:Thiophenes