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Soares LA, Nascimento LMM, Guimarães FS, Gazarini L, Bertoglio LJ. Dual-step pharmacological intervention for traumatic-like memories: implications from D-cycloserine and cannabidiol or clonidine in male and female rats. Psychopharmacology (Berl) 2024:10.1007/s00213-024-06596-8. [PMID: 38691149 DOI: 10.1007/s00213-024-06596-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 04/19/2024] [Indexed: 05/03/2024]
Abstract
RATIONALE Therapeutic approaches to mitigating traumatic memories have often faced resistance. Exploring safe reconsolidation blockers, drugs capable of reducing the emotional valence of the memory upon brief retrieval and reactivation, emerges as a promising pharmacological strategy. Towards this objective, preclinical investigations should focus on aversive memories resulting in maladaptive outcomes and consider sex-related differences to enhance their translatability. OBJECTIVES After selecting a relatively high training magnitude leading to the formation of a more intense and generalized fear memory in adult female and male rats, we investigated whether two clinically approved drugs disrupting its reconsolidation remain effective. RESULTS We found resistant reconsolidation impairment by the α2-adrenergic receptor agonist clonidine or cannabidiol, a major non-psychotomimetic Cannabis sativa component. However, pre-retrieval administration of D-cycloserine, a partial agonist at the glycine-binding site of the N-methyl-D-aspartate (NMDA) receptor complex, facilitated their impairing effects on reconsolidation. A similar reconsolidation blockade by clonidine or cannabidiol was achieved following exposure to a non-conditioned but generalized context after D-cycloserine administration. This suggests that sufficient memory destabilization can accompany generalized fear expression. Combining clonidine with cannabidiol without potentiating memory destabilization by D-cycloserine was ineffective. CONCLUSIONS These findings highlight the importance of NMDA receptor signaling in memory destabilization and underscore the efficacy of a dual-step pharmacological intervention in attenuating traumatic-like memories, even in a context different from the original learning environment.
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Affiliation(s)
- Luciane A Soares
- Departamento de Farmacologia, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | - Laura M M Nascimento
- Departamento de Farmacologia, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | | | - Lucas Gazarini
- Universidade Federal de Mato Grosso Do Sul, Três Lagoas, MS, Brazil
| | - Leandro J Bertoglio
- Universidade Federal de Mato Grosso Do Sul, Três Lagoas, MS, Brazil.
- Depto. de Farmacologia, CCB, UFSC, Campus Universitário S/N, Florianópolis, SC, 88049-900, Brazil.
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2
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Matias ME, Radulski DR, Rodrigues da Silva T, Raymundi AM, Stern CAJ, Zampronio AR. Involvement of cannabinoid receptors and neuroinflammation in early sepsis: Implications for posttraumatic stress disorder. Int Immunopharmacol 2023; 123:110745. [PMID: 37541107 DOI: 10.1016/j.intimp.2023.110745] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 07/20/2023] [Accepted: 07/29/2023] [Indexed: 08/06/2023]
Abstract
Sepsis is associated with several comorbidities in survivors, such as posttraumatic stress disorder (PTSD). This study investigated whether rats that survive sepsis develop the generalization of fear memory as a model of PTSD. Responses to interventions that target the endothelin-1 (ET-1)/cannabinoid system and glial activation in the initial stages of sepsis were evaluated. As a control, we evaluated hyperalgesia before fear conditioning. Sepsis was induced by cecal ligation and puncture (CLP) in Wistar rats. CLP-induced sepsis with one or three punctures resulted in fear generalization in the survivors 13 and 20 days after the CLP procedure, a process that was not associated with hyperalgesia. Septic animals were intracerebroventricularly treated with vehicle, the endothelin receptor A (ETA) antagonist BQ123, the cannabinoid CB1 and CB2 receptor antagonists AM251 and AM630, respectively, and the glial blocker minocycline 4 h after CLP. The blockade of either CB1 or ETA receptors increased the survival rate, but only the former reversed fear memory generalization. The endothelinergic system blockade is important for improving survival but not for fear memory. Treatment with the CB2 receptor antagonist or minocycline also reversed the generalization of fear memory but did not increase the survival rate that was associated with CLP. Minocycline treatment also reduced tumor necrosis factor-α levels in the hippocampus suggesting that neuroinflammation is important for the generalization of fear memory induced by CLP. The influence of CLP on the generalization of fear memory was not related to Arc protein expression, a regulator of synaptic plasticity, in the dorsal hippocampus.
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Affiliation(s)
| | | | | | - Ana Maria Raymundi
- Department of Pharmacology, Federal University of Paraná, Curitiba, PR, Brazil
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Silva BA, Gräff J. Face your fears: attenuating remote fear memories by reconsolidation-updating. Trends Cogn Sci 2023; 27:404-416. [PMID: 36813591 DOI: 10.1016/j.tics.2023.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 01/22/2023] [Accepted: 01/23/2023] [Indexed: 02/22/2023]
Abstract
Traumatic events generate some of the most enduring memories, yet little is known about how long-lasting fear memories can be attenuated. In this review, we collect the surprisingly sparse evidence on remote fear memory attenuation from both animal and human research. What is becoming apparent is twofold: although remote fear memories are more resistant to change compared with recent ones, they can nevertheless be attenuated when interventions are targeted toward the period of memory malleability instigated by memory recall, the reconsolidation window. We describe the physiological mechanisms underlying remote reconsolidation-updating approaches and highlight how they can be enhanced through interventions promoting synaptic plasticity. By capitalizing on an intrinsically relevant phase of memory, reconsolidation-updating harbors the potential to permanently alter remote fear memories.
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Affiliation(s)
- Bianca A Silva
- National Research Council of Italy, Institute of Neuroscience, Milan, Italy; IRCCS Humanitas Research Hospital, Rozzano, Milan, Italy
| | - Johannes Gräff
- Laboratory of Neuroepigenetics, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale Lausanne (EPFL), Switzerland.
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Raymundi AM, Batista Sohn JM, Salemme BW, Cardoso NC, Silveira Guimarães F, Stern CA. Effects of delta-9 tetrahydrocannabinol on fear memory labilization and reconsolidation: A putative role of GluN2B-NMDA receptor within the dorsal hippocampus. Neuropharmacology 2023; 225:109386. [PMID: 36549374 DOI: 10.1016/j.neuropharm.2022.109386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 12/14/2022] [Accepted: 12/17/2022] [Indexed: 12/23/2022]
Abstract
Cannabis preparations could be an effective reconsolidation-based treatment for post-traumatic stress disorder. However, the effects of Δ9-tetrahydrocannabinol (THC) in fear memory labilization, a critical condition for retrieval-induced reconsolidation, are undetermined. We sought to investigate the effect of a conventional and an ultra-low dose of THC in memory labilization of adult male Wistar rats submitted to contextual fear conditioning. Pretreatment with THC 0.002, but not THC 0.3 mg/kg, i. p., before memory retrieval, did not change memory expression during the retrieval but impaired reconsolidation. No treatment changed freezing expression in an unpaired context. Before retrieval, THC 0.3, but not THC 0.002, decreased GluN2A-NMDA expression and the GluN2A/GluN2B ratio in the dorsal hippocampus (DH) 24 h later. No changes were observed immediately after retrieval. Pretreatment with THC 0.3 abolished the reconsolidation-impairing effect of anisomycin injected into the DH, suggesting an impairment in memory labilization. This effect was associated with an increased freezing expression in the unpaired context and was not observed with the THC ultra-low dose. The GluN2B-NMDA antagonism increased fear generalization in the anisomycin-treated group but restored its reconsolidation-impairing effect and reduced fear generalization when animals were pretreated with THC 0.3. GluN2A-NMDA antagonism or inhibition of the ubiquitin-proteasome system in the DH did not interfere with the effects of THC 0.3. Our findings indicate that THC causes a bidirectional effect on fear memory labilization that depends on hippocampal GluN2B-NMDA receptors' involvement in fear memory generalization.
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Affiliation(s)
- Ana Maria Raymundi
- Department of Pharmacology, Federal University of Parana, Curitiba, PR, Brazil
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5
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Bozic I, Rusterholz T, Mikutta C, Del Rio-Bermudez C, Nissen C, Adamantidis A. Coupling between the prelimbic cortex, nucleus reuniens, and hippocampus during NREM sleep remains stable under cognitive and homeostatic demands. Eur J Neurosci 2023; 57:106-128. [PMID: 36310348 DOI: 10.1111/ejn.15853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 09/28/2022] [Accepted: 10/05/2022] [Indexed: 02/02/2023]
Abstract
The interplay between the medial prefrontal cortex and hippocampus during non-rapid eye movement (NREM) sleep contributes to the consolidation of contextual memories. To assess the role of the thalamic nucleus reuniens (Nre) in this interaction, we investigated the coupling of neuro-oscillatory activities among prelimbic cortex, Nre, and hippocampus across sleep states and their role in the consolidation of contextual memories using multi-site electrophysiological recordings and optogenetic manipulations. We showed that ripples are time-locked to the Up state of cortical slow waves, the transition from UP to DOWN state in thalamic slow waves, the troughs of cortical spindles, and the peaks of thalamic spindles during spontaneous sleep, rebound sleep and sleep following a fear conditioning task. In addition, spiking activity in Nre increased before hippocampal ripples, and the phase-locking of hippocampal ripples and thalamic spindles during NREM sleep was stronger after acquisition of a fear memory. We showed that optogenetic inhibition of Nre neurons reduced phase-locking of ripples to cortical slow waves in the ventral hippocampus whilst their activation altered the preferred phase of ripples to slow waves in ventral and dorsal hippocampi. However, none of these optogenetic manipulations of Nre during sleep after acquisition of fear conditioning did alter sleep-dependent memory consolidation. Collectively, these results showed that Nre is central in modulating hippocampus and cortical rhythms during NREM sleep.
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Affiliation(s)
- Ivan Bozic
- Zentrum für Experimentelle Neurologie, Department of Neurology, Inselspital University Hospital Bern, Bern, Switzerland.,Department of Biomedical Research, University of Bern, Bern, Switzerland
| | - Thomas Rusterholz
- Zentrum für Experimentelle Neurologie, Department of Neurology, Inselspital University Hospital Bern, Bern, Switzerland.,Department of Biomedical Research, University of Bern, Bern, Switzerland
| | - Christian Mikutta
- University Hospital of Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland.,Privatklinik Meiringen, Meiringen, Switzerland.,Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Carlos Del Rio-Bermudez
- Zentrum für Experimentelle Neurologie, Department of Neurology, Inselspital University Hospital Bern, Bern, Switzerland.,Department of Biomedical Research, University of Bern, Bern, Switzerland
| | - Christoph Nissen
- University Hospital of Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland
| | - Antoine Adamantidis
- Zentrum für Experimentelle Neurologie, Department of Neurology, Inselspital University Hospital Bern, Bern, Switzerland.,Department of Biomedical Research, University of Bern, Bern, Switzerland.,Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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6
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Franzen JM, Vanz F, Werle I, Guimarães FS, Bertoglio LJ. Cannabidiol impairs fear memory reconsolidation in female rats through dorsal hippocampus CB1 but not CB2 receptor interaction. Eur Neuropsychopharmacol 2022; 64:7-18. [PMID: 36049316 DOI: 10.1016/j.euroneuro.2022.08.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 08/11/2022] [Accepted: 08/14/2022] [Indexed: 01/23/2023]
Abstract
Women present increased susceptibility to anxiety- and stress-related disorders compared to men. A potentially promising pharmacological-based strategy to regulate abnormal aversive memories disrupts their reconsolidation stage after reactivation and destabilization. Male rodent findings indicate that cannabidiol (CBD), a relatively safe and effective treatment for several mental health conditions, can impair the reconsolidation of aversive memories. However, whether and how CBD influences it in females is still unknown. The present study addressed this question in contextually fear-conditioned female rats. We report that systemically administered CBD impaired their reconsolidation, reducing freezing expression for over a week. This action was restricted to a time when the reconsolidation presumably lasted (< six hours post-retrieval) and depended on memory reactivation/destabilization. Moreover, the impairing effects of CBD on memory reconsolidation relied on the activation of cannabinoid type-1 but not type-2 receptors located in the CA1 subregion of the dorsal hippocampus. CBD applied directly to this brain area was sufficient to reproduce the effects of systemic CBD treatment. Contextual fear memories attenuated by CBD did not show reinstatement, an extinction-related feature. By demonstrating that destabilized fear memories are sensitive to CBD and how it hinders mechanisms in the DH CA1 that may restabilize them in female rats, the present findings concur that reconsolidation blockers are viable and could be effective in disrupting abnormally persistent and distressing aversive memories such as those related to posttraumatic stress disorder.
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Affiliation(s)
- Jaqueline M Franzen
- Departamento de Farmacologia, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | - Felipe Vanz
- Departamento de Farmacologia, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | - Isabel Werle
- Departamento de Farmacologia, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | | | - Leandro J Bertoglio
- Departamento de Farmacologia, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil.
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7
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Wang SH. Lose the fear and boost the everyday memory through memory destabilisation and reconsolidation. Brain Res Bull 2022; 190:134-139. [DOI: 10.1016/j.brainresbull.2022.09.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 09/12/2022] [Accepted: 09/24/2022] [Indexed: 11/02/2022]
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8
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Vasudevan K, Ramanathan KR, Vierkant V, Maren S. Nucleus reuniens inactivation does not impair consolidation or reconsolidation of fear extinction. LEARNING & MEMORY (COLD SPRING HARBOR, N.Y.) 2022; 29:216-222. [PMID: 35902273 PMCID: PMC9374271 DOI: 10.1101/lm.053611.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 07/01/2022] [Indexed: 11/24/2022]
Abstract
Recent data reveal that the thalamic nucleus reuniens (RE) has a critical role in the extinction of conditioned fear. Muscimol (MUS) infusions into the RE impair within-session extinction of conditioned freezing and result in poor long-term extinction memories in rats. Although this suggests that RE inactivation impairs extinction learning, it is also possible that it is involved in the consolidation of extinction memories. To examine this possibility, we examined the effects of RE inactivation on the consolidation and reconsolidation of fear extinction in male and female rats. Twenty-four hours after auditory fear conditioning, rats underwent an extinction procedure (45 CS-alone trials) in a novel context and were infused with saline (SAL) or MUS within minutes of the final extinction trial. Twenty-four hours later, conditioned freezing to the extinguished CS was assessed in the extinction context. Postextinction inactivation of the RE did not affect extinction retrieval. In a second experiment, rats underwent extinction training and, 24 h later, were presented with a single CS to reactivate the extinction memory; rats were infused with SAL or MUS immediately after the reactivation session. Pharmacological inactivation of the RE did not affect conditioned freezing measured in a drug-free retrieval test the following day. Importantly, we found in a subsequent test that MUS infusions immediately before retrieval testing increased conditioned freezing and impaired extinction retrieval, as we have previously reported. These results indicate that although RE inactivation impairs the expression of extinction, it does not impair either the consolidation or reconsolidation of extinction memories. We conclude that the RE may have a critical role in suppressing context-inappropriate fear memories in the extinction context.
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Affiliation(s)
- Krithika Vasudevan
- Department of Psychological and Brain Sciences, Institute for Neuroscience, Texas A&M University, College Station, Texas 77843, USA
| | - Karthik R Ramanathan
- Department of Psychological and Brain Sciences, Institute for Neuroscience, Texas A&M University, College Station, Texas 77843, USA
| | - Valerie Vierkant
- Department of Psychological and Brain Sciences, Institute for Neuroscience, Texas A&M University, College Station, Texas 77843, USA
| | - Stephen Maren
- Department of Psychological and Brain Sciences, Institute for Neuroscience, Texas A&M University, College Station, Texas 77843, USA
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9
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Medial prefrontal cortex mechanisms of cannabidiol-induced aversive memory reconsolidation impairments. Neuropharmacology 2021; 205:108913. [PMID: 34864001 DOI: 10.1016/j.neuropharm.2021.108913] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 11/15/2021] [Accepted: 11/30/2021] [Indexed: 02/08/2023]
Abstract
Growing evidence indicates that cannabidiol (CBD), a substance present in the Cannabis sativa plant, has potential therapeutic value to regulate abnormal emotional memories associated with post-traumatic stress and drug use disorders. CBD can attenuate their valence after retrieval (i.e., during reconsolidation) or potentiate their suppression by extinction. Pharmacological research has now focused on elucidating how it acts. Systemic antagonism of cannabinoid type-1 (CB1) receptors has often prevented the abovementioned effects of CBD. However, it is unknown in which brain regions CBD stimulates CB1 receptors and how it interferes with local activity-related plasticity to produce these effects. The present study addressed these questions considering the reconsolidation of contextual fear memories in rats. We focused on the medial prefrontal cortex (mPFC), which comprises the anterior cingulate (AC), prelimbic (PL), and infralimbic (IL) subregions, as local activity or plasticity has been associated with the process to-be-investigated. Animals that received post-retrieval systemic CBD treatment presented relatively fewer cells expressing Zif268/Egr1 protein, a proxy for synaptic plasticity related to reconsolidation, in the AC and PL. At the same time, there were no significant differences in the IL. Pretreatment with the CB1 receptor antagonist/inverse agonist AM251 into the AC, PL, or IL prevented the impairing effects of systemic CBD treatment on reconsolidation. CBD also caused reconsolidation impairments when injected directly into the AC or PL but not the IL. Together, these findings show complementary mechanisms through which CBD may hinder the reconsolidation of destabilized aversive memories along the dorsoventral axis of the mPFC.
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10
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Roughley S, Killcross S. The role of the infralimbic cortex in decision making processes. Curr Opin Behav Sci 2021. [DOI: 10.1016/j.cobeha.2021.06.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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11
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Troyner F, Bertoglio LJ. Nucleus reuniens of the thalamus controls fear memory reconsolidation. Neurobiol Learn Mem 2020; 177:107343. [PMID: 33242589 DOI: 10.1016/j.nlm.2020.107343] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 11/08/2020] [Accepted: 11/16/2020] [Indexed: 01/09/2023]
Abstract
The nucleus reuniens has been shown to support the acquisition, consolidation, maintenance, destabilization upon retrieval, and extinction of aversive memories. However, the direct participation of this thalamic subregion in memory reconsolidation is yet to be examined. The present study addressed this question in contextually fear-conditioned rats. Post-reactivation infusion of the GABAA receptor agonist muscimol, the glutamate N2A-containing NMDA receptor antagonist TCN-201, or the protein synthesis inhibitor anisomycin into the NR induced significant impairments in memory reconsolidation. Administering muscimol or TCN-201 and anisomycin locally, or associating locally infused muscimol or TCN-201 with systemically administered clonidine, an α2-receptor adrenergic agonist that attenuates the noradrenergic tonus associated with memory reconsolidation, produced no further reduction in freezing times when compared with the muscimol-vehicle, TCN-201-vehicle, vehicle-anisomycin, and vehicle-clonidine groups. This pattern of results indicates that such treatment combinations produced no additive/synergistic effects on reconsolidation. It is plausible that NR inactivation and antagonism of glutamate N2A-containing NMDA receptors weakened/prevented the subsequent action of anisomycin and clonidine because they disrupted the early stages of signal transduction pathways involved in memory reconsolidation. It is noteworthy that these pharmacological interventions, either alone or combined, induced no contextual memory specificity changes, as assessed in a later test in a novel and unpaired context. Besides, omitting memory reactivation precluded the impairing effects of muscimol, TCN-201, anisomycin, and clonidine on reconsolidation. Together, the present findings demonstrate interacting mechanisms through which the NR can regulate contextual fear memory restabilization.
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Affiliation(s)
- Fernanda Troyner
- Departamento de Farmacologia, Universidade Federal de Santa Catarina, Florianopolis, SC, Brazil
| | - Leandro Jose Bertoglio
- Departamento de Farmacologia, Universidade Federal de Santa Catarina, Florianopolis, SC, Brazil.
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Marin FN, Franzen JM, Troyner F, Molina VA, Giachero M, Bertoglio LJ. Taking advantage of fear generalization-associated destabilization to attenuate the underlying memory via reconsolidation intervention. Neuropharmacology 2020; 181:108338. [PMID: 33002500 DOI: 10.1016/j.neuropharm.2020.108338] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 09/24/2020] [Accepted: 09/26/2020] [Indexed: 02/05/2023]
Abstract
Upon retrieval, an aversive memory can undergo destabilization and reconsolidation. A traumatic-like memory, however, may be resistant to this process. The present study sought to contribute with a strategy to overcome this potential issue by investigating whether generalized fear retrieval is susceptible to destabilization-reconsolidation that can be pharmacologically modified. We hypothesized that exposure to a context that elicits moderate generalization levels would allow a malleable memory state. We developed a fear conditioning protocol in context A (cxt-A) paired with yohimbine administration to promote significant fear to a non-conditioned context B (cxt-B) in rats, mimicking the enhanced noradrenergic activity reported after traumatic events in humans. Next, we attempted to impair the reconsolidation phase by administering clonidine (CLO) immediately after exposure to cxt-A, cxt-B, or a third context C (cxt-C) neither conditioned nor generalized. CLO administered post-cxt-B exposure for two consecutive days subsequently resulted in decreased freezing levels in cxt-A. CLO after cxt-B only once, after cxt-A or cxt-C in two consecutive days, or independently of cxt-B exposures did not affect fear in a later test. A 6-h-delay in CLO treatment post-cxt-B exposures produced no effects, and nimodipine administered pre-cxt-B exposures precluded the CLO action. We then quantified the Egr1/Zif268 protein expression following cxt-B exposures and CLO treatments. We found that these factors interact to modulate this memory destabilization-reconsolidation mechanism in the basolateral amygdala but not the dorsal CA1 hippocampus. Altogether, memory destabilization can accompany generalized fear expression; thus, we may exploit it to potentiate reconsolidation blockers' action.
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Affiliation(s)
- Fernanda Navarro Marin
- Departamento de Farmacologia, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | - Jaqueline Maisa Franzen
- Departamento de Farmacologia, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | - Fernanda Troyner
- Departamento de Farmacologia, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | - Victor Alejandro Molina
- Departamento de Farmacología, IFEC-CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Marcelo Giachero
- Departamento de Farmacologia, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil; Instituto de Neurociencia Cognitiva y Traslacional (INCYT), CONICET, Fundación INECO, Universidad Favaloro, Buenos Aires, Argentina.
| | - Leandro Jose Bertoglio
- Departamento de Farmacologia, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil.
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