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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
25
pubmed:dateCreated
2003-12-3
pubmed:abstractText
The hydrogen-bond-acceptor properties of the carbonyl moiety in the 17beta-acetyl group on the D-ring of the anesthetic steroids (3alpha,5alpha)- and (3alpha,5beta)-3-hydroxypregan-20-one form an important part of the anesthetic steroid pharmacophore. 13,24-Cyclo-18,21-dinorcholanes containing a ketone or conjugated ketone group at C-20, C-22, C-23, or C-24 were prepared as conformationally constrained analogues of these anesthetic steroids and were used to probe for alternate locations for the D-ring hydrogen-bond-accepting carbonyl group. The analogues were evaluated (1). in [(35)S]-tert-butylbicyclophosphorothionate binding experiments, (2). in electrophysiological experiments using rat alpha(1)beta(2)gamma(2L) GABA(A) receptors expressed in Xenopus laevis oocytes, and (3). as tadpole anesthetics. In the binding assay, the relative order of potencies for the analogues in the 5alpha- and 5beta-series is identical. For the ketones, the order is 24-one >or= 23-one > 20-one > 22-one. Likewise, for the enones, the order is delta(22)-24-one > delta(20(22))-23-one > delta(22)-20-one > delta(23)-22-one. Similar relative orders of potencies are also found in the other two bioassays. The activities of the 24-one and delta(22)-24-one compounds were expected to be very low, because the carbonyl group in these compounds is located over the steroid C-ring and oriented toward C-8. Instead, these compounds have the highest activities in their respective series, with the delta(22)-24-one compounds having activities comparable to those of the reference anesthetic steroids. The electrophysiology results obtained with the 24-oxo-cyclosteroids suggest that rat alpha(1)beta(2)gamma(2L) GABA(A) receptors contain more than one donor for the hydrogen-bond-acceptor group of anesthetic steroids. The family of cyclosteroids should be useful for future structure-activity relationship studies of steroid modulation of other GABA(A) receptor subtypes.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0022-2623
pubmed:author
pubmed:issnType
Print
pubmed:day
4
pubmed:volume
46
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5334-48
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Neurosteroid analogues. 9. Conformationally constrained pregnanes: structure-activity studies of 13,24-cyclo-18,21-dinorcholane analogues of the GABA modulatory and anesthetic steroids (3alpha,5alpha)- and (3alpha,5beta)-3-hydroxypregnan-20-one.
pubmed:affiliation
Department of Molecular Biology, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, Missouri 63110, USA.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't