BACKGROUND: D-cycloserine (DCS), a partial N-methyl-D-aspartate (NMDA) agonist, facilitates the extinction of conditioned fear in animals and promotes the efficacy of exposure-based therapies in humans. The current study examined whether pre-exposure to the antidepressant imipramine affects the enhancement of extinction by DCS. METHODS: Twenty-nine rats were pre-exposed to saline, DCS, or imipramine for 14 days. The next day they were given five noise-shock pairings. The day after training, rats received six extinction trials and were then injected with DCS. At test the following day, freezing elicited by the noise was measured. RESULTS: Rats pre-exposed to either DCS or imipramine exhibited more freezing at test than rats pre-exposed to saline. CONCLUSIONS: Chronic exposure to either DCS or imipramine prevents the facilitating effect of DCS on extinction. This result suggests that DCS may not effectively enhance loss of fear in patients who are also being treated with antidepressants.
BACKGROUND:D-cycloserine (DCS), a partial N-methyl-D-aspartate (NMDA) agonist, facilitates the extinction of conditioned fear in animals and promotes the efficacy of exposure-based therapies in humans. The current study examined whether pre-exposure to the antidepressant imipramine affects the enhancement of extinction by DCS. METHODS: Twenty-nine rats were pre-exposed to saline, DCS, or imipramine for 14 days. The next day they were given five noise-shock pairings. The day after training, rats received six extinction trials and were then injected with DCS. At test the following day, freezing elicited by the noise was measured. RESULTS:Rats pre-exposed to either DCS or imipramine exhibited more freezing at test than rats pre-exposed to saline. CONCLUSIONS: Chronic exposure to either DCS or imipramine prevents the facilitating effect of DCS on extinction. This result suggests that DCS may not effectively enhance loss of fear in patients who are also being treated with antidepressants.
Authors: Michael W Otto; M Alexandra Kredlow; Jasper A J Smits; Stefan G Hofmann; David F Tolin; Rianne A de Kleine; Agnes van Minnen; A Eden Evins; Mark H Pollack Journal: Biol Psychiatry Date: 2015-09-25 Impact factor: 13.382
Authors: Patricia Bado; Caroline Madeira; Charles Vargas-Lopes; Thiago C Moulin; Ana Paula Wasilewska-Sampaio; Luise Maretti; Ricardo V de Oliveira; Olavo B Amaral; Rogério Panizzutti Journal: Psychopharmacology (Berl) Date: 2011-05-10 Impact factor: 4.530