Lack of drug-induced post-retrieval amnesia for auditory fear memories in rats
Abstract Background Long-term memory formation is generally assumed to involve the permanent storage of recently acquired memories, making them relatively insensitive to disruption, a process referred to as memory consolidation. However, when retrieved under specific circumstances, consolidated fear...
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| Format: | Article |
| Language: | English |
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BMC
2021-01-01
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| Series: | BMC Biology |
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| Online Access: | https://doi.org/10.1186/s12915-021-00957-x |
| _version_ | 1818329521250631680 |
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| author | Laura Luyten Anna Elisabeth Schnell Natalie Schroyens Tom Beckers |
| author_facet | Laura Luyten Anna Elisabeth Schnell Natalie Schroyens Tom Beckers |
| author_sort | Laura Luyten |
| collection | DOAJ |
| description | Abstract Background Long-term memory formation is generally assumed to involve the permanent storage of recently acquired memories, making them relatively insensitive to disruption, a process referred to as memory consolidation. However, when retrieved under specific circumstances, consolidated fear memories are thought to return to a labile state, thereby opening a window for modification (e.g., attenuation) of the memory. Several interventions during a critical time frame after this destabilization seem to be able to alter the retrieved memory, for example by pharmacologically interfering with the restabilization process, either by direct protein synthesis inhibition or indirectly, using drugs that can be safely administered in patients (e.g., propranolol). Here, we find that, contrary to expectations, systemic pharmacological manipulations in auditory fear-conditioned rats do not lead to drug-induced post-retrieval amnesia. Results In a series of well-powered auditory fear conditioning experiments (four with propranolol, 10 mg/kg, two with rapamycin, 20–40 mg/kg, one with anisomycin, 150 mg/kg and cycloheximide, 1.5 mg/kg), we found no evidence for reduced cued fear memory expression during a drug-free test in adult male Sprague-Dawley rats that had previously received a systemic drug injection upon retrieval of the tone fear memory. All experiments used standard fear conditioning and reactivation procedures with freezing as the behavioral read-out (conceptual or exact replications of published reports) and common pharmacological agents. Additional tests confirmed that the applied drug doses and administration routes were effective in inducing their conventional effects on expression of fear (propranolol, acutely), body weight (rapamycin, anisomycin, cycloheximide), and consolidation of extinction memories (cycloheximide). Conclusions In contrast with previously published studies, we did not find evidence for drug-induced post-retrieval amnesia, underlining that this effect, as well as its clinical applicability, may be considerably more constrained and less readily reproduced than what the current literature would suggest. |
| first_indexed | 2024-12-13T12:49:23Z |
| format | Article |
| id | doaj.art-086aa662a5bc43aca6b5a8bc81726b61 |
| institution | Directory Open Access Journal |
| issn | 1741-7007 |
| language | English |
| last_indexed | 2024-12-13T12:49:23Z |
| publishDate | 2021-01-01 |
| publisher | BMC |
| record_format | Article |
| series | BMC Biology |
| spelling | doaj.art-086aa662a5bc43aca6b5a8bc81726b612022-12-21T23:45:22ZengBMCBMC Biology1741-70072021-01-0119111510.1186/s12915-021-00957-xLack of drug-induced post-retrieval amnesia for auditory fear memories in ratsLaura Luyten0Anna Elisabeth Schnell1Natalie Schroyens2Tom Beckers3KU Leuven, Faculty of Psychology and Educational Sciences, Psychology of Learning and Experimental PsychopathologyKU Leuven, Faculty of Psychology and Educational Sciences, Psychology of Learning and Experimental PsychopathologyKU Leuven, Faculty of Psychology and Educational Sciences, Psychology of Learning and Experimental PsychopathologyKU Leuven, Faculty of Psychology and Educational Sciences, Psychology of Learning and Experimental PsychopathologyAbstract Background Long-term memory formation is generally assumed to involve the permanent storage of recently acquired memories, making them relatively insensitive to disruption, a process referred to as memory consolidation. However, when retrieved under specific circumstances, consolidated fear memories are thought to return to a labile state, thereby opening a window for modification (e.g., attenuation) of the memory. Several interventions during a critical time frame after this destabilization seem to be able to alter the retrieved memory, for example by pharmacologically interfering with the restabilization process, either by direct protein synthesis inhibition or indirectly, using drugs that can be safely administered in patients (e.g., propranolol). Here, we find that, contrary to expectations, systemic pharmacological manipulations in auditory fear-conditioned rats do not lead to drug-induced post-retrieval amnesia. Results In a series of well-powered auditory fear conditioning experiments (four with propranolol, 10 mg/kg, two with rapamycin, 20–40 mg/kg, one with anisomycin, 150 mg/kg and cycloheximide, 1.5 mg/kg), we found no evidence for reduced cued fear memory expression during a drug-free test in adult male Sprague-Dawley rats that had previously received a systemic drug injection upon retrieval of the tone fear memory. All experiments used standard fear conditioning and reactivation procedures with freezing as the behavioral read-out (conceptual or exact replications of published reports) and common pharmacological agents. Additional tests confirmed that the applied drug doses and administration routes were effective in inducing their conventional effects on expression of fear (propranolol, acutely), body weight (rapamycin, anisomycin, cycloheximide), and consolidation of extinction memories (cycloheximide). Conclusions In contrast with previously published studies, we did not find evidence for drug-induced post-retrieval amnesia, underlining that this effect, as well as its clinical applicability, may be considerably more constrained and less readily reproduced than what the current literature would suggest.https://doi.org/10.1186/s12915-021-00957-xFear conditioningAuditory fearRatsPost-retrieval amnesiaReconsolidationConsolidation |
| spellingShingle | Laura Luyten Anna Elisabeth Schnell Natalie Schroyens Tom Beckers Lack of drug-induced post-retrieval amnesia for auditory fear memories in rats BMC Biology Fear conditioning Auditory fear Rats Post-retrieval amnesia Reconsolidation Consolidation |
| title | Lack of drug-induced post-retrieval amnesia for auditory fear memories in rats |
| title_full | Lack of drug-induced post-retrieval amnesia for auditory fear memories in rats |
| title_fullStr | Lack of drug-induced post-retrieval amnesia for auditory fear memories in rats |
| title_full_unstemmed | Lack of drug-induced post-retrieval amnesia for auditory fear memories in rats |
| title_short | Lack of drug-induced post-retrieval amnesia for auditory fear memories in rats |
| title_sort | lack of drug induced post retrieval amnesia for auditory fear memories in rats |
| topic | Fear conditioning Auditory fear Rats Post-retrieval amnesia Reconsolidation Consolidation |
| url | https://doi.org/10.1186/s12915-021-00957-x |
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