Oxytocin and Social Support as Synergistic Inhibitors of Aversive Fear Conditioning and Fear-Potentiated Startle in Male Rats
Annual rept. 1 Mar 2009-31 Aug 2010
DELAWARE UNIV NEWARK
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The purpose of the grant is to test whether exogenous oxytocin acts as an antianxiety agent and whether social support facilitates its antianxiety effects in a fear-potentiated startle paradigm. Oxytocin given systemically 0.1 microgramskg, sc effectively reduced background anxiety, but not specific cue-potentiated fear. This was found when oxytocin was given either before fear conditioning acquisition, immediately after fear conditioning consolidation, or before retrievalexpression of conditioned fear-potentiated startle. Social isolation for 3 weeks potentiated startle this was reversed by oxytocin. Intracerebroventricular infusion of oxytocin only reduced background anxiety with a very large dose 20 micrograms, suggesting indirect action in brain. It is concluded that oxytocin has unique antianxiety properties that reduce background and social-isolation anxiety -- anxiety states not directly related to cue-specific fear, but are sustained beyond the immediate threat. Oxytocin might be promising as a drug with novel benefits for patients with PTSD.