Oxytocin and Social Support as Synergistic Inhibitors of Aversive Fear Conditioning and Fear-Potentiated Startle in Male Rats

• Main Author: Rosen, Jeff
• Format: Report
• Language: English
• Subjects: ANTIANXIETY AGENTS; ANXIETY; DRUGS; FEAR; OXYTOCIN; Pharmacology; PITUITARY HORMONES; POST TRAUMATIC STRESS DISORDER; Psychology; RATS; SOCIAL ISOLATION; STARTLE

We found exogenous oxytocin acts as an antianxiety agent in a fear-potentiated startle paradigm. Oxytocin given systemically (0.1 micrograms/kg, sc) effectively reduced background anxiety, but not specific cue-potentiated fear, when given before fear conditioning (acquisition), immediately after fear conditioning (consolidation), or before retrieval/expression of conditioned fear-potentiated startle. In contrast, oxytocin infused into the lateral ventricle only reduced background anxiety with a very large dose (20 micrograms). We conclude that oxytocin uniquely reduces background anxiety -- an anxiety state not directly related to cue-specific fear, but sustained beyond the immediate threat. The findings also indicate that oxytocin acts as an antianxiety agent peripherally to then affect brain through indirect mechanisms. Promising initial data with a paradigm of potentiated startle after 3 weeks of social isolation have been difficult to replicate. We suggest oxytocin is promising as a drug with novel benefits for patients with PTSD. The original document contains color images.