AbstractBackground and PurposeNeurosteroids are allosteric modulators of GABAA currents, acting through several functional binding sites although their affinity and specificity for each site are unknown. The goal of this study was to measure steady‐state binding affinities of various neurosteroids for specific sites on the GABAA receptor.Experimental ApproachTwo methods were developed to measure neurosteroid binding affinity: (1) quenching of specific tryptophan residues in neurosteroid binding sites by the neurosteroid 17‐methylketone group, and (2) FRET between MQ290 (an intrinsically fluorescent neurosteroid) and tryptophan residues in the binding sites. The assays were developed using ELIC‐α1GABAAR, a chimeric receptor containing transmembrane domains of the α1‐GABAA receptor. Tryptophan mutagenesis was used to identify specific interactions.Key ResultsAllopregnanolone (3α‐OH neurosteroid) was shown to bind at intersubunit and intrasubunit sites with equal affinity, whereas epi‐allopregnanolone (3β‐OH neurosteroid) binds at the intrasubunit site. MQ290 formed a strong FRET pair with W246, acting as a site‐specific probe for the intersubunit site. The affinity and site‐specificity of several neurosteroid agonists and inverse agonists was measured using the MQ290 binding assay. The FRET assay distinguishes between competitive and allosteric inhibition of MQ290 binding and demonstrated an allosteric interaction between the two neurosteroid binding sites.Conclusions and ImplicationsThe affinity and specificity of neurosteroid binding to two sites in the ELIC‐α1GABAAR were directly measured and an allosteric interaction between the sites was revealed. Adaptation of the MQ290 FRET assay to a plate‐reader format will enable screening for high affinity agonists and antagonists for neurosteroid binding sites.
Conformationally Constrained Anesthetic Steroids That Modulate GABA<sub>A</sub> Receptors
作者:Alison Anderson、Andrew C. Boyd、John K. Clark、Lee Fielding、David K. Gemmell、Niall M. Hamilton、Maurice S. Maidment、Valerie May、Ross McGuire、Petula McPhail、Francis H. Sansbury、Hardy Sundaram、Robert Taylor
DOI:10.1021/jm000977e
日期:2000.11.1
alpha-hydroxyandrostane derivatives bearing a conformationally constrained hydrogen-bonding moiety were prepared. Their anesthetic potency and their binding affinity for GABA(A) receptors, measured by intravenous administration to mice and inhibition of [(35)S]TBPS binding to rat whole brain membranes, were compared with that of known anesthetic 3 alpha-hydroxypregnan-20-ones. Synthetic steroids with similar
NEUROACTIVE 19-ALKOXY-17-SUBSTITUTED STEROIDS, PRODRUGS THEREOF, AND METHODS OF TREATMENT USING SAME
申请人:Sage Therapeutics, Inc.
公开号:US20140235600A1
公开(公告)日:2014-08-21
The present disclosure is generally directed to neuroactive 19-alkoxy-17-substituted steroids as referenced herein, and pharmaceutically acceptable salts thereof, for use as, for example, an anesthetic, and/or in the treatment of disorders relating to GABA function and activity. The present disclosure is further directed to pharmaceutical compositions comprising such compounds.
Neuroactive 3.alpha.-hydroxy-steroids of the androstane and pregnane series
申请人:Purdue Pharma Ltd.
公开号:EP1288220A2
公开(公告)日:2003-03-05
The invention relates to a 3α-hydroxy, 17-(un)substituted derivatives of the androstane series and 3α-hydroxy, 21-substituted derivatives of the pregnane series. These derivatives are capable of acting at the recently identified site on the GRC, thereby modulating brain excitability in a manner that will alleviate stress, anxiety, insomnia, mood disorders that are amenable to GRC-active agents (such as depression) and seizure activity. The steroid derivatives of this invention are those having general structural formula (I), wherein R, R1, R2, R3,R4, R5, R6, R7, R8, R9 and R10 are further defined herein and the dotted lines are single or double bonds. The structure includes androstanes pregnanes (R4 = methyl), 19-norandrostanes, and norpregnanes (R4=H).