Effects of D-cycloserine on extinction of conditioned freezing.
The present study tested the prediction that D-cycloserine (DCS), a partial N-methyl-D-aspartate agonist, would facilitate extinction of conditioned freezing in male Sprague-Dawley rats. Rats received 5 light-shock pairings (conditioning). The following day, rats received 6 light-alone presentations (extinction training). Twenty-four hours later, rats received 1 light-alone presentation (test). Subcutaneous DCS injection before or after extinction training significantly enhanced extinction, and the dose-response curve for this effect was linear. Increasing the delay of DCS administration after extinction training led to a linear decrease in the facilitatory effect. The effect of systemic administration was replicated by intra-basolateral amygdala infusion. These results suggest that DCS facilitates extinction of conditioned freezing by acting on consolidation processes partly mediated by the basolateral amygdala.
Ledgerwood
Lana
L
School of Psychology, University of New South Wales, Sydney, Australia. lledgerwood@psy.unsw.edu.au
Richardson
Rick
R
Cranney
Jacquelyn
J
D000679:Amygdala / Q000187:drug effects; D000704:Analysis of Variance; D000818:Animals; D001931:Brain Mapping; D003213:Conditioning, Psychological / Q000187:drug effects* / Q000502:physiology; D003523:Cycloserine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004333:Drug Administration Routes / Q000662:veterinary; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology*; D005108:Extinction, Psychological / Q000187:drug effects* / Q000502:physiology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013216:Reflex, Startle / Q000187:drug effects* / Q000502:physiology; D013997:Time Factors
D018690:Excitatory Amino Acid Agonists; D003523:Cycloserine