The effect of D-cycloserine on immediate vs. delayed extinction of learned fear.
We compared the effect of D-cycloserine (DCS) on immediate (10 min after conditioning) and delayed (24 h after conditioning) extinction of learned fear in rats. DCS facilitated both immediate and delayed extinction when the drug was administered after extinction training. However, DCS did not facilitate immediate extinction when administered prior to extinction training (i.e., when the interval between drug administration and shock was reduced). In addition, administering five, but not two, shocks prior to extinction training disrupted the facilitating effects of DCS on delayed extinction. These results suggest that aversive experiences prior to DCS administration can prevent it from facilitating extinction.
Adult Cancer Program, Prince of Wales Clinical School, University of New South Wales, Sydney 2052, Australia. j.langton@unsw.edu.au
Julia M
JM
Langton
Rick
R
Richardson
D000818:Animals; D000963:Antimetabolites / Q000494:pharmacology*; D003214:Conditioning, Classical / Q000187:drug effects*; D003523:Cycloserine / Q000494:pharmacology*; D004597:Electroshock / Q000009:adverse effects; D005108:Extinction, Psychological / Q000187:drug effects*; D005239:Fear / Q000187:drug effects*; D051381:Rats; D013997:Time Factors
D000963:Antimetabolites; D003523:Cycloserine