title: Effects of oxytocin on background anxiety in rats with high or low baseline startle.
abstract: Oxytocin has antianxiety properties in humans and rodents. However, the antianxiety effects have been variable.
  
  
  
  To reduce variability and to strengthen the antianxiety effect of oxytocin in fear-potentiated startle, two experiments were performed. First, different amounts of light-shock pairings were given to determine the optimal levels of cue-specific fear conditioning and non-predictable startle (background anxiety). Second, the antianxiety effects of oxytocin were examined in rats with high and low pre-fear conditioning baseline startle to determine if oxytocin differentially affects high and low trait anxiety rats.
  
  
  
  Baseline pre-fear conditioning startle responses were first measured. Rats then received 1, 5, or 10 light-shock pairings. Fear-potentiated startle was then tested with two trial types: light-cued startle and non-cued startle trials. In the second experiment, rats fear conditioned with 10 light-shock pairings were administered either saline or oxytocin before a fear-potentiated startle test. Rats were categorized as low or high startlers by their pre-fear conditioning startle amplitude.
  
  
  
  Ten shock pairings produced the largest non-cued startle responses (background anxiety), without increasing cue-specific fear-potentiated startle compared to one and five light-shock pairings. Cue-specific fear-potentiated startle was unaffected by oxytocin. Oxytocin reduced background anxiety only in rats with low pre-fear startle responses.
  
  
  
  Oxytocin has population selective antianxiety effects on non-cued unpredictable threat, but only in rats with low pre-fear baseline startle responses. The low startle responses are reminiscent of humans with low startle responses and high trait anxiety.
authors.affiliation: Department of Psychology, Widener University, Chester, PA, USA.
authors.forename: Luke
authors.initials: L
authors.lastname: Ayers
authors.affiliation: Department of Psychological and Brain Sciences, University of Delaware, Newark, DE, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Agostini
authors.affiliation: Department of Neuroscience, Georgetown University, Washington, DC, USA.
authors.forename: Jay
authors.initials: J
authors.lastname: Schulkin
authors.affiliation: Department of Psychological and Brain Sciences, University of Delaware, Newark, DE, USA. jrosen@udel.edu.
authors.forename: Jeffrey B
authors.initials: JB
authors.lastname: Rosen
mesh_terms: D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D001007:Anxiety / Q000523:psychology*; D003213:Conditioning, Psychological / Q000187:drug effects; D003463:Cues; D004597:Electroshock; D005239:Fear / Q000523:psychology; D008297:Male; D010121:Oxytocin / Q000494:pharmacology*; D010775:Photic Stimulation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013216:Reflex, Startle / Q000187:drug effects*
chemical_list: D014151:Anti-Anxiety Agents; D010121:Oxytocin
keywords: Anxiety; Fear; Oxytocin; Startle