title: Response-rate suppression in operant paradigm as predictor of soporific potency in rats and identification of three novel sedative-hypnotic neuroactive steroids.
abstract: Novel neuroactive steroids were evaluated for their effects on operant responding, rotorod motor performance, and electroencephalogram recording in rats. Co 134444, Co 177843, and Co 127501 were compared with the prototypical gamma-aminobutyric acid(A)-positive allosteric modulators triazolam, zolpidem, pentobarbital, pregnanolone, and CCD 3693. Each of the compounds produced a dose-related decrease in response rates under a variable-interval 2-min schedule of positive reinforcement in an operant paradigm. In addition, all compounds produced a dose-related increase in ataxia and significant increases in nonrapid eye movement sleep in this experiment or have been previously reported to do so. Co 134444, Co 177843, and Co 127501 increased nonrapid eye movement sleep at doses that had no effect on rapid eye movement sleep. All of the compounds were more potent at decreasing operant responding than they were at increasing ataxia. Furthermore, the potency of compounds to produce response-rate suppression in an operant paradigm appeared to be a better predictor of soporific potency than did potency in the rotorod assay. The screening for sedative-hypnotic activity resulted in the identification of the novel orally active neuroactive steroids Co 134444, Co 177843, and Co 127501.
authors.affiliation: CoCensys, Inc., Irvine, California 92618, USA. kvanover@cocensys.com
authors.forename: K E
authors.initials: KE
authors.lastname: Vanover
authors.forename: D M
authors.initials: DM
authors.lastname: Edgar
authors.forename: W F
authors.initials: WF
authors.lastname: Seidel
authors.forename: D J
authors.initials: DJ
authors.lastname: Hogenkamp
authors.forename: D B
authors.initials: DB
authors.lastname: Fick
authors.forename: N C
authors.initials: NC
authors.lastname: Lan
authors.forename: K W
authors.initials: KW
authors.lastname: Gee
authors.forename: R B
authors.initials: RB
authors.lastname: Carter
mesh_terms: D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects*; D003864:Depression, Chemical; D004305:Dose-Response Relationship, Drug; D004569:Electroencephalography / Q000187:drug effects; D006993:Hypnotics and Sedatives / Q000494:pharmacology*; D008297:Male; D010424:Pentobarbital / Q000494:pharmacology; D004856:Postural Balance / Q000187:drug effects; D011280:Pregnanolone / Q000031:analogs & derivatives / Q000494:pharmacology; D011284:Pregnenolone / Q000031:analogs & derivatives / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D013256:Steroids / Q000494:pharmacology*; D014229:Triazolam / Q000494:pharmacology; D000077334:Zolpidem
chemical_list: C401849:Co 127501; C401851:Co 177843; D006993:Hypnotics and Sedatives; D011725:Pyridines; D013256:Steroids; C107043:CCD 3693; C401850:Co 134444; D014229:Triazolam; D011284:Pregnenolone; D000077334:Zolpidem; D011280:Pregnanolone; D010424:Pentobarbital