title: Evaluation of the neuroactive steroid ganaxolone on social and repetitive behaviors in the BTBR mouse model of autism.
abstract: BACKGROUND
  Abnormalities in excitatory/inhibitory neurotransmission are hypothesized to contribute to autism spectrum disorder (ASD) etiology. BTBR T (+) Itpr3 (tf) /J (BTBR), an inbred mouse strain, displays social deficits and repetitive self-grooming, offering face validity to ASD diagnostic symptoms. Reduced GABAergic neurotransmission in BTBR suggests that GABAA receptor positive allosteric modulators (PAMs) could improve ASD-relevant BTBR phenotypes. The neuroactive steroid ganaxolone acts as a PAM, displaying anticonvulsant properties in rodent epilepsy models and an anxiolytic-like profile in the elevated plus-maze.
  
  
  OBJECTIVE
  We evaluated ganaxolone in BTBR and C57BL/6J mice in standardized assays for sociability and repetitive behaviors. Open field and anxiety-related behaviors were tested as internal controls and for comparison with the existing neuroactive steroid literature.
  
  
  RESULTS
  Ganaxolone improved aspects of social approach and reciprocal social interactions in BTBR, with no effect on repetitive self-grooming, and no detrimental effects in C57BL/6J. Ganaxolone increased overall exploratory activity in BTBR and C57BL/6J in the open field, social approach, and elevated plus-maze, introducing a confound for the interpretation of social improvements. Allopregnanolone and diazepam similarly increased total entries in the elevated plus-maze, indicating that behavioral activation may be a general property of GABAA receptor PAMs in these strains.
  
  
  CONCLUSIONS
  Ganaxolone shows promise for improving sociability. In addition, ganaxolone, as well as other GABAA receptor PAMs, enhanced overall BTBR activity. The translational implications of specific sociability improvements and nonspecific behavioral activation by ganaxolone in the BTBR model remain to be determined. Future studies to explore whether PAMs provide a novel profile with unique benefits for ASD treatment will be worthwhile.
authors.affiliation: MIND Institute, Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, 95817, USA. tkazdoba@ucdavis.edu.
authors.forename: Tatiana M
authors.initials: TM
authors.lastname: Kazdoba
authors.affiliation: MIND Institute, Department of Pediatrics, University of California Davis School of Medicine, Sacramento, CA, USA.
authors.forename: Randi J
authors.initials: RJ
authors.lastname: Hagerman
authors.affiliation: Department of Neurology, University of California Davis School of Medicine, Sacramento, CA, USA.
authors.forename: Dorota
authors.initials: D
authors.lastname: Zolkowska
authors.affiliation: Department of Neurology, University of California Davis School of Medicine, Sacramento, CA, USA.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Rogawski
authors.affiliation: MIND Institute, Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, 95817, USA.
authors.forename: Jacqueline N
authors.initials: JN
authors.lastname: Crawley
mesh_terms: D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology*; D001007:Anxiety / Q000523:psychology; D001321:Autistic Disorder / Q000235:genetics* / Q000523:psychology*; D001522:Behavior, Animal / Q000187:drug effects*; D003975:Diazepam / Q000494:pharmacology; D005260:Female; D018757:GABA Modulators / Q000494:pharmacology*; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000235:genetics*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009043:Motor Activity / Q000187:drug effects; D011280:Pregnanolone / Q000031:analogs & derivatives* / Q000494:pharmacology; D011963:Receptors, GABA-A / Q000187:drug effects; D012919:Social Behavior
chemical_list: D000927:Anticonvulsants; D018757:GABA Modulators; C582634:ITPR3 protein, mouse; D053496:Inositol 1,4,5-Trisphosphate Receptors; D011963:Receptors, GABA-A; C105051:ganaxolone; D011280:Pregnanolone; D003975:Diazepam
keywords: Allopregnanolone; Anxiety; Autism spectrum disorder; Diazepam; Ganaxolone; Neuroactive steroid; Open field; Repetitive behaviors; Sociability; Social approach