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Effects of multiple exposures to D-cycloserine on extinction of conditioned fear in rats.
Neurobiol Learn Mem. 2005 May; 83(3):224-31.NL

Abstract

Previous research has shown that an acute, post-training injection of D-cycloserine (DCS) facilitates extinction of conditioned fear in rats; however, the effects of multiple exposures to DCS in this situation are not known. In Experiment 1, rats were conditioned (light-shock pairings) and 24 h later given six extinction (light-alone) trials followed by an injection of DCS (15 mg/kg) or saline. The next day, all rats were tested for light-elicited freezing. In Experiment 2, the effect of DCS on extinction was tested in the same manner, except that rats were pre-exposed to DCS (0, 1, or 5 injections) just prior to conditioning. In Experiment 3, rats received five pre-exposures of DCS but conditioning occurred either 2 or 28 days after the last pre-exposure. The results showed that DCS facilitated extinction of conditioned freezing to the light CS when no drug pre-exposure had occurred, but pre-exposure to DCS just prior to conditioning disrupted the facilitation of extinction effect. When 28 days were interposed between pre-exposure and conditioning, the facilitatory effects of DCS on extinction were restored. These findings suggest that DCS has significant clinical value but that behavioral desensitization may occur with multiple exposures; however, desensitization is not permanent and is reduced by the passage of time.

Authors+Show Affiliations

School of Psychology, University of New South Wales, Sydney 2052, Australia.No affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15820858

Citation

Parnas, A Sophie, et al. "Effects of Multiple Exposures to D-cycloserine On Extinction of Conditioned Fear in Rats." Neurobiology of Learning and Memory, vol. 83, no. 3, 2005, pp. 224-31.
Parnas AS, Weber M, Richardson R. Effects of multiple exposures to D-cycloserine on extinction of conditioned fear in rats. Neurobiol Learn Mem. 2005;83(3):224-31.
Parnas, A. S., Weber, M., & Richardson, R. (2005). Effects of multiple exposures to D-cycloserine on extinction of conditioned fear in rats. Neurobiology of Learning and Memory, 83(3), 224-31.
Parnas AS, Weber M, Richardson R. Effects of Multiple Exposures to D-cycloserine On Extinction of Conditioned Fear in Rats. Neurobiol Learn Mem. 2005;83(3):224-31. PubMed PMID: 15820858.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Effects of multiple exposures to D-cycloserine on extinction of conditioned fear in rats. AU - Parnas,A Sophie, AU - Weber,Marianne, AU - Richardson,Rick, PY - 2004/04/16/received PY - 2004/09/21/revised PY - 2005/01/01/accepted PY - 2005/4/12/pubmed PY - 2005/7/23/medline PY - 2005/4/12/entrez SP - 224 EP - 31 JF - Neurobiology of learning and memory JO - Neurobiol Learn Mem VL - 83 IS - 3 N2 - Previous research has shown that an acute, post-training injection of D-cycloserine (DCS) facilitates extinction of conditioned fear in rats; however, the effects of multiple exposures to DCS in this situation are not known. In Experiment 1, rats were conditioned (light-shock pairings) and 24 h later given six extinction (light-alone) trials followed by an injection of DCS (15 mg/kg) or saline. The next day, all rats were tested for light-elicited freezing. In Experiment 2, the effect of DCS on extinction was tested in the same manner, except that rats were pre-exposed to DCS (0, 1, or 5 injections) just prior to conditioning. In Experiment 3, rats received five pre-exposures of DCS but conditioning occurred either 2 or 28 days after the last pre-exposure. The results showed that DCS facilitated extinction of conditioned freezing to the light CS when no drug pre-exposure had occurred, but pre-exposure to DCS just prior to conditioning disrupted the facilitation of extinction effect. When 28 days were interposed between pre-exposure and conditioning, the facilitatory effects of DCS on extinction were restored. These findings suggest that DCS has significant clinical value but that behavioral desensitization may occur with multiple exposures; however, desensitization is not permanent and is reduced by the passage of time. SN - 1074-7427 UR - https://www.unboundmedicine.com/medline/citation/15820858/Effects_of_multiple_exposures_to_D_cycloserine_on_extinction_of_conditioned_fear_in_rats_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S1074-7427(05)00003-1 DB - PRIME DP - Unbound Medicine ER -