ABSTRACT
Return to use, or relapse, is a major challenge in the treatment of opioid use disorder (OUD). Relapse can be precipitated by several factors, including exposure to drug-conditioned cues. Identifying successful treatments to mitigate cue-induced relapse has been challenging, perhaps due to extinction memory recall (EMR) deficits. Previously, inhibition of estradiol (E2) signaling in the basolateral amygdala (BLA) impaired heroin-cue EMR. This effect was recapitulated by antagonism of BLA estrogen receptors (ER) in a sex-specific manner such that blocking ERα in males, but ERß in females, impaired EMR. However, it is unclear whether increased E2 signaling, in the BLA or systemically, enhances heroin-cue EMR. We hypothesized that ERß agonism would enhance heroin-cue EMR in a sex- and region-specific manner. To determine the capacity of E2 signaling to improve EMR, we pharmacologically manipulated ERß across several translationally designed experiments. First, male and female rats acquired heroin or sucrose self-administration. Next, during a cued extinction session, we administered diarylpropionitrile (DPN, an ERß agonist) and tested anxiety-like behavior on an open field. Subsequently, we assessed EMR in a cue-induced reinstatement test and, finally, measured ERß expression in several brain regions. Across all experiments, females took more heroin and sucrose than males and had greater responses during heroin-cued extinction. Administration of DPN in the BLA enhanced EMR in females only, driven by ERß's impacts on memory consolidation. Interestingly, however, systemic DPN administration improved EMR for heroin cues in both sexes across several different tests, but did not impact sucrose-cue EMR. Immunohistochemical analysis of ERß expression across several different brain regions showed that females only had greater expression of ERß in the basal nucleus of the BLA. Here, in several preclinical experiments, we demonstrated that ERß agonism enhances heroin-cue EMR and has potential utility in combatting cue-induced relapse.
Subject(s)
Cues , Estrogen Receptor beta , Extinction, Psychological , Heroin , Mental Recall , Animals , Male , Female , Estrogen Receptor beta/agonists , Estrogen Receptor beta/metabolism , Heroin/pharmacology , Rats , Extinction, Psychological/drug effects , Extinction, Psychological/physiology , Mental Recall/drug effects , Mental Recall/physiology , Nitriles/pharmacology , Basolateral Nuclear Complex/metabolism , Basolateral Nuclear Complex/drug effects , Propionates/pharmacology , Sex Factors , Self Administration , Rats, Sprague-Dawley , Heroin Dependence/metabolism , Signal Transduction/drug effectsABSTRACT
Despite significant advances in the study of fear and fear memory formation, little is known about fear learning and expression in females. This omission has been proven surprising, as normal and pathological behaviors are highly influenced by ovarian hormones, particularly estradiol and progesterone. In the current study, we investigated the joint influence of serotonin (5-HT) neurotransmission and estrous cycle phases (low or high levels of estradiol and progesterone) on the expression of conditioned fear in a group of female rats that were previously divided according to their response to stressful stimuli into low or high anxiety-like subjects. The baseline amplitude of the unconditioned acoustic startle responses was high in high-anxiety female rats, with no effect on the estrous cycle observed. Data collected during the proestrus-estrus phase revealed that low-anxiety rats had startle amplitudes similar to those of high-anxiety rats. It is supposed that high-anxiety female rats benefit from increased estradiol and progesterone levels to achieve comparable potentiated startle amplitudes. In contrast, female rats experienced a significant decrease in hormone levels during the Diestrus phase. This decrease is believed to play a role in preventing them from displaying a heightened startle response when faced with strongly aversive stimuli. Data collected after 5-HT and 8-OH-DPAT were administered into the basolateral nuclei and dorsal periaqueductal gray suggest that 5-HT neurotransmission works with progesterone and estrogen to reduce startle potentiation, most likely by activating the serotonin-1A receptor subtype.
Subject(s)
Basolateral Nuclear Complex , Estradiol , Fear , Periaqueductal Gray , Progesterone , Receptor, Serotonin, 5-HT1A , Reflex, Startle , Animals , Female , Rats , Anxiety/metabolism , Anxiety/physiopathology , Basolateral Nuclear Complex/metabolism , Basolateral Nuclear Complex/drug effects , Conditioning, Classical/physiology , Conditioning, Classical/drug effects , Estradiol/pharmacology , Estradiol/metabolism , Estrous Cycle/physiology , Fear/physiology , Fear/drug effects , Periaqueductal Gray/metabolism , Periaqueductal Gray/drug effects , Progesterone/pharmacology , Progesterone/metabolism , Rats, Wistar , Receptor, Serotonin, 5-HT1A/metabolism , Reflex, Startle/physiology , Reflex, Startle/drug effects , Serotonin/metabolismABSTRACT
The pivotal role of the basolateral amygdala (BLA) in the emotional modulation of hippocampal plasticity and memory consolidation is well-established. Specifically, multiple studies have demonstrated that the activation of the noradrenergic (NA) system within the BLA governs these modulatory effects. However, most current evidence has been obtained by direct infusion of synthetic NA or beta-adrenergic agonists. In the present study, we aimed to investigate the effect of endogenous NA release in the BLA, induced by a natural aversive stimulus (coyote urine), on memory consolidation for a low-arousing, hippocampal-dependent task. Our experiments combined a weak object location task (OLT) version with subsequent mild predator odor exposure (POE). To investigate the role of endogenous NA in the BLA in memory modulation, a subset of the animals (Wistar rats) was treated with the non-selective beta-blocker propranolol at the end of the behavioral procedures. Hippocampal tissue was collected 90 min after drug infusion or after the OLT test, which was performed 24 h later. We used the obtained samples to estimate the levels of phosphorylated CREB (pCREB) and activity-regulated cytoskeleton-associated protein (Arc)-two molecular markers of experience-dependent changes in neuronal activity. The result suggests that POE has the potential to become a valuable behavioral paradigm for studying the interaction between BLA and the hippocampus in memory prioritization and selectivity.
Subject(s)
Basolateral Nuclear Complex , Emotions , Hippocampus , Memory Consolidation , Norepinephrine , Odorants , Rats, Wistar , Animals , Memory Consolidation/physiology , Memory Consolidation/drug effects , Basolateral Nuclear Complex/metabolism , Basolateral Nuclear Complex/physiology , Basolateral Nuclear Complex/drug effects , Male , Rats , Norepinephrine/metabolism , Hippocampus/metabolism , Hippocampus/physiology , Hippocampus/drug effects , Emotions/physiology , Emotions/drug effects , Cyclic AMP Response Element-Binding Protein/metabolism , Propranolol/pharmacologyABSTRACT
The advent of general anesthesia (GA) has significant implications for clinical practice. However, the exact mechanisms underlying GA-induced transitions in consciousness remain elusive. Given some similarities between GA and sleep, the sleep-arousal neural nuclei and circuits involved in sleep-arousal, including the 5-HTergic system, could be implicated in GA. Herein, we utilized pharmacology, optogenetics, chemogenetics, fiber photometry, and retrograde tracing to demonstrate that both endogenous and exogenous activation of the 5-HTergic neural circuit between the dorsal raphe nucleus (DR) and basolateral amygdala (BLA) promotes arousal and facilitates recovery of consciousness from sevoflurane anesthesia. Notably, the 5-HT1A receptor within this pathway holds a pivotal role. Our findings will be conducive to substantially expanding our comprehension of the neural circuit mechanisms underlying sevoflurane anesthesia and provide a potential target for modulating consciousness, ultimately leading to a reduction in anesthetic dose requirements and side effects.
Subject(s)
Anesthetics, Inhalation , Basolateral Nuclear Complex , Consciousness , Dorsal Raphe Nucleus , Sevoflurane , Sevoflurane/pharmacology , Animals , Dorsal Raphe Nucleus/drug effects , Dorsal Raphe Nucleus/metabolism , Consciousness/drug effects , Anesthetics, Inhalation/pharmacology , Basolateral Nuclear Complex/drug effects , Basolateral Nuclear Complex/metabolism , Basolateral Nuclear Complex/physiology , Male , Mice , Mice, Inbred C57BL , Serotonin/metabolism , Neural Pathways/drug effects , Neural Pathways/physiology , Receptor, Serotonin, 5-HT1A/metabolism , OptogeneticsABSTRACT
Single administration of low-dose ketamine has both acute and sustained anti-depressant effects. Sustained effect is associated with restoration of glutamatergic synapses in medial prefrontal cortic (mFPC) neurons. Ketamine induced profound changes in a number of molecular pathways in a mouse model for chronic stress. Cell-cell communication analyses predicted that planar-cell-polarity (PCP) signaling was decreased after chronic administration of corticosterone but increased following ketamine administration in most of the excitatory neurons. Similar decrease of PCP signaling in excitatory neurons was predicted in dorsolateral prefrontal cortical (dl-PFC) neurons of patients with major depressive disorder (MDD). We showed that the basolateral amygdala (BLA)-projecting infralimbic prefrontal cortex (IL PFC) neurons regulate immobility time in the tail suspension test and food consumption. Conditionally knocking out Celsr2 and Celsr3 or Prickle2 in the BLA-projecting IL PFC neurons abolished ketamine-induced synapse restoration and behavioral remission. Therefore, PCP proteins in IL PFC-BLA neurons mediate synapse restoration induced by of low-dose ketamine.
Subject(s)
Disease Models, Animal , Ketamine , Neurons , Prefrontal Cortex , Synapses , Animals , Ketamine/pharmacology , Prefrontal Cortex/metabolism , Prefrontal Cortex/drug effects , Synapses/drug effects , Synapses/metabolism , Neurons/metabolism , Neurons/drug effects , Mice , Male , Humans , Cell Polarity/drug effects , Depressive Disorder, Major/metabolism , Depressive Disorder, Major/drug therapy , Mice, Knockout , Stress, Psychological , Corticosterone , Basolateral Nuclear Complex/metabolism , Basolateral Nuclear Complex/drug effects , Mice, Inbred C57BL , LIM Domain Proteins/metabolism , LIM Domain Proteins/genetics , Glutamic Acid/metabolism , Antidepressive Agents/pharmacologyABSTRACT
The neural mechanisms underlying paternal care in biparental mammals are not well understood. The California mouse (Peromyscus californicus) is a biparental rodent in which virtually all fathers are attracted to pups, while virgin males vary widely in their behavior toward unrelated infants, ranging from attacking to avoiding to huddling and grooming pups. We previously showed that pharmacologically inhibiting the synthesis of the neurotransmitter norepinephrine (NE) with the dopamine ß-hydroxylase inhibitor nepicastat reduced the propensity of virgin male and female California mice to interact with pups. The current study tested the hypothesis that nepicastat would reduce pup-induced c-Fos immunoreactivity, a cellular marker of neural activity, in the medial preoptic area (MPOA), medial amygdala (MeA), basolateral amygdala (BLA), and bed nucleus of the stria terminalis (BNST), brain regions implicated in the control of parental behavior and/or anxiety. Virgin males were injected with nepicastat (75â¯mg/kg, i.p.) or vehicle 2â¯hours prior to exposure to either an unrelated pup or novel object for 60â¯minutes (n = 4-6 mice per group). Immediately following the 60-minute stimulus exposure, mice were euthanized and their brains were collected for c-Fos immunohistochemistry. Nepicastat reduced c-Fos expression in the MeA and MPOA of pup-exposed virgin males compared to vehicle-injected controls. In contrast, nepicastat did not alter c-Fos expression in any of the above brain regions following exposure to a novel object. Overall, these results suggest that the noradrenergic system might influence MeA and MPOA function to promote behavioral interactions with pups in virgin males.
Subject(s)
Dopamine beta-Hydroxylase , Paternal Behavior , Peromyscus , Preoptic Area , Septal Nuclei , Animals , Male , Dopamine beta-Hydroxylase/metabolism , Dopamine beta-Hydroxylase/antagonists & inhibitors , Paternal Behavior/physiology , Paternal Behavior/drug effects , Septal Nuclei/drug effects , Septal Nuclei/metabolism , Preoptic Area/metabolism , Preoptic Area/drug effects , Proto-Oncogene Proteins c-fos/metabolism , Female , Enzyme Inhibitors/pharmacology , Basolateral Nuclear Complex/drug effects , Basolateral Nuclear Complex/metabolism , Corticomedial Nuclear Complex/drug effects , Corticomedial Nuclear Complex/metabolism , Norepinephrine/metabolism , Imidazoles , ThionesABSTRACT
The anteroventral bed nucleus of stria terminalis (avBNST) is a limbic forebrain region involved in the regulation of anxiety, and expresses GABAB receptors, which are located at both pre- and post-synaptic sites. However, it is unclear how blockade of these receptors affects anxiety-like behaviors, particularly in Parkinson's disease (PD)-related anxiety. In the present study, unilateral 6-hydroxydopamine (6-OHDA) lesions of the substantia nigra pars compacta in rats induced anxiety-like behaviors, and increased GABA release and decreased glutamate release in the avBNST, as well as decreased level of dopamine (DA) in the basolateral amygdala (BLA). Intra-avBNST injection of pre-synaptic GABAB receptor antagonist CGP36216 produced anxiolytic-like effects, while the injection of post-synaptic GABAB receptor antagonist CGP35348 induced anxiety-like responses in both sham and 6-OHDA rats. Intra-avBNST injection of CGP36216 inhibited the GABAergic neurons and increased GABA/glutamate ratio in the avBNST and increased levels of DA and serotonin (5-HT) in the BLA; conversely, CGP35348 produced opposite effects on the firing activity of avBNST GABAergic neurons and levels of the neurotransmitters in the avBNST and BLA. Moreover, the doses of the antagonists producing significant behavioral effects in 6-OHDA rats were lower than those in sham rats, and the duration of action of the antagonists on the firing rate of the neurons and release of the neurotransmitters was prolonged in 6-OHDA rats. Altogether, these findings suggest that pre- and post-synaptic GABAB receptors in the avBNST are implicated in PD-related anxiety-like behaviors, and degeneration of the nigrostriatal pathway enhances functions and/or upregulates expression of these receptors.
Subject(s)
Anti-Anxiety Agents , Anxiety , GABA-B Receptor Antagonists , Oxidopamine , Parkinsonian Disorders , Receptors, GABA-B , Septal Nuclei , Animals , Septal Nuclei/drug effects , Septal Nuclei/metabolism , Male , Anxiety/metabolism , GABA-B Receptor Antagonists/pharmacology , Anti-Anxiety Agents/pharmacology , Rats , Receptors, GABA-B/metabolism , Oxidopamine/toxicity , Parkinsonian Disorders/metabolism , Parkinsonian Disorders/chemically induced , Parkinsonian Disorders/psychology , Dopamine/metabolism , Glutamic Acid/metabolism , gamma-Aminobutyric Acid/metabolism , Rats, Sprague-Dawley , Serotonin/metabolism , Basolateral Nuclear Complex/metabolism , Basolateral Nuclear Complex/drug effects , GABAergic Neurons/drug effects , GABAergic Neurons/metabolism , Organophosphorus CompoundsABSTRACT
The ventral pallidum (VP) receives its primary inputs from the nucleus accumbens (NAC) and the basolateral amygdala (BLA). We demonstrated recently that in the VP, the D2 DA receptor (D2R) agonist quinpirole dose-dependently facilitates memory consolidation in inhibitory avoidance and spatial learning. In the VP, D2R can be found both on NAC and BLA terminals. According to our hypothesis, quinpirole microinjected into the VP can facilitate memory consolidation via modulation of synaptic plasticity on NAC and/or BLA terminals. The effect of intra-VP quinpirole on BLA-VP and NAC shell-VP synapses was investigated via a high frequency stimulation (HFS) protocol. Quinpirole was administered in three doses into the VP of male Sprague-Dawley rats after HFS; controls received vehicle. To examine whether an interaction between the NAC shell and the BLA at the level of the VP was involved, tetrodotoxin (TTX) was microinjected into one of the nuclei while stimulating the other nucleus. Our results showed that quinpirole dose-dependently modulates BLA-VP and NAC shell-VP synapses, similar to those observed in inhibitory avoidance and spatial learning, respectively. The lower dose inhibits BLA inputs, while the larger doses facilitates NAC shell inputs. The experiments with TTX demonstrates that the two nuclei do not influence each others' evoked responses in the VP. Power spectral density analysis demonstrated that independent from the synaptic facilitation, intra-VP quinpirole increases the amplitude of gamma frequency band after NAC HFS, and BLA tonically suppresses the NAC's HFS-induced gamma facilitation. In contrast, HFS of the BLA results in a delayed, transient increase in the amplitude of the gamma frequency band correlating with the LTP of the P1 component of the VP response to BLA stimulation. Furthermore, our results demonstrate that the BLA plays a prominent role in the generation of the delta oscillations: HFS of the BLA leads to a gradually increasing delta frequency band facilitation over time, while BLA inhibition blocks the NAC's HFS induced strong delta facilitation. These findings demonstrate that there is a complex interaction between the NAC shell region and the VP, as well as the BLA and the VP, and support the important role of VP D2Rs in the regulation of limbic information flow.
Subject(s)
Basal Forebrain , Dopamine Agonists , Dose-Response Relationship, Drug , Microinjections , Quinpirole , Rats, Sprague-Dawley , Receptors, Dopamine D2 , Animals , Quinpirole/pharmacology , Male , Basal Forebrain/drug effects , Basal Forebrain/physiology , Receptors, Dopamine D2/agonists , Receptors, Dopamine D2/drug effects , Rats , Dopamine Agonists/pharmacology , Dopamine Agonists/administration & dosage , Nucleus Accumbens/drug effects , Nucleus Accumbens/physiology , Limbic System/drug effects , Limbic System/physiology , Electric Stimulation , Basolateral Nuclear Complex/drug effects , Basolateral Nuclear Complex/physiologyABSTRACT
Selective serotonin reuptake inhibitors, such as fluoxetine (Prozac), are commonly prescribed pharmacotherapies for anxiety. Fluoxetine may be a useful adjunct because it can reduce the expression of learned fear in adult rodents. This effect is associated with altered expression of perineuronal nets (PNNs) in the amygdala and hippocampus, two brain regions that regulate fear. However, it is unknown whether fluoxetine has similar effects in adolescents. Here, we investigated the effect of fluoxetine exposure during adolescence or adulthood on context fear memory and PNNs in the basolateral amygdala (BLA), the CA1 subregion of the hippocampus, and the medial prefrontal cortex in rats. Fluoxetine impaired context fear memory in adults but not in adolescents. Further, fluoxetine increased the number of parvalbumin (PV)-expressing neurons surrounded by a PNN in the BLA and CA1, but not in the medial prefrontal cortex, at both ages. Contrary to previous reports, fluoxetine did not shift the percentage of PNNs toward non-PV cells in either the BLA or CA1 in the adults, or adolescents. These findings demonstrate that fluoxetine differentially affects fear memory in adolescent and adult rats but does not appear to have age-specific effects on PNNs.
Subject(s)
Fear , Fluoxetine , Memory , Prefrontal Cortex , Selective Serotonin Reuptake Inhibitors , Fluoxetine/pharmacology , Fluoxetine/administration & dosage , Animals , Fear/drug effects , Fear/physiology , Male , Rats , Selective Serotonin Reuptake Inhibitors/pharmacology , Selective Serotonin Reuptake Inhibitors/administration & dosage , Prefrontal Cortex/drug effects , Memory/drug effects , Memory/physiology , Age Factors , Rats, Sprague-Dawley , Parvalbumins/metabolism , Basolateral Nuclear Complex/drug effects , Basolateral Nuclear Complex/metabolism , CA1 Region, Hippocampal/drug effects , Nerve Net/drug effectsABSTRACT
Chronic morphine withdrawal memory formation is a complex process influenced by various molecular mechanisms. In this study, we aimed to investigate the contributions of the basolateral amygdala (BLA) and complement component 1, q subcomponent-like 3 (C1QL3), a secreted and presynaptically targeted protein, to the formation of chronic morphine (repeat dosing of morphine) withdrawal memory using conditioned place aversion (CPA) and chemogenetic methods. We conducted experiments involving the inhibition of the BLA during naloxone-induced withdrawal to assess its impact on CPA scores, providing insights into the significance of the BLA in the chronic morphine memory formation process. We also examined changes in C1ql3/C1QL3 expression within the BLA following conditioning. Immunofluorescence analysis revealed the colocalization of C1QL3 and the G protein-coupled receptor, brain-specific angiogenesis inhibitor 3 (BAI3) in the BLA, supporting their involvement in synaptic development. Moreover, we downregulated C1QL3 expression in the BLA to investigate its role in chronic morphine withdrawal memory formation. Our findings revealed that BLA inhibition during naloxone-induced withdrawal led to a significant reduction in CPA scores, confirming the critical role of the BLA in this memory process. Additionally, the upregulation of C1ql3 expression within the BLA postconditioning suggested its participation in withdrawal memory formation. The colocalization of C1QL3 and BAI3 in the BLA further supported their involvement in synaptic development. Furthermore, downregulation of C1QL3 in the BLA effectively hindered chronic morphine withdrawal memory formation, emphasizing its pivotal role in this process. Notably, we identified postsynaptic density protein 95 (PSD95) as a potential downstream effector of C1QL3 during chronic morphine withdrawal memory formation. Blocking PSD95 led to a significant reduction in the CPA score, and it appeared that C1QL3 modulated the ubiquitination-mediated degradation of PSD95, resulting in decreased PSD95 protein levels. This study underscores the importance of the BLA, C1QL3 and PSD95 in chronic morphine withdrawal memory formation. It provides valuable insights into the underlying molecular mechanisms, emphasizing their significance in this intricate process.
Subject(s)
Basolateral Nuclear Complex , Disks Large Homolog 4 Protein , Memory , Morphine , Substance Withdrawal Syndrome , Animals , Morphine/pharmacology , Substance Withdrawal Syndrome/metabolism , Male , Mice , Memory/drug effects , Disks Large Homolog 4 Protein/metabolism , Basolateral Nuclear Complex/metabolism , Basolateral Nuclear Complex/drug effects , Complement C1q/metabolism , Mice, Inbred C57BL , Naloxone/pharmacologyABSTRACT
Background: Anxiety and social withdrawal are highly prevalent among patients with Alzheimer's disease (AD). However, the neural circuit mechanisms underlying these symptoms remain elusive, and there is a need for effective prevention strategies. Objective: This study aims to elucidate the neural circuitry mechanisms underlying social anxiety in AD. Methods: We utilized 5xFAD mice and conducted a series of experiments including optogenetic manipulation, Tandem Mass Tag-labeled proteome analysis, behavioral assessments, and immunofluorescence staining. Results: In 5xFAD mice, we observed significant amyloid-ß (Aß) accumulation in the anterior part of basolateral amygdala (aBLA). Behaviorally, 6-month-old 5xFAD mice displayed excessive social avoidance during social interaction. Concurrently, the pathway from aBLA to ventral hippocampal CA1 (vCA1) was significantly activated and exhibited a disorganized firing patterns during social interaction. By optogenetically inhibiting the aBLA-vCA1 pathway, we effectively improved the social ability of 5xFAD mice. In the presence of Aß accumulation, we identified distinct changes in the protein network within the aBLA. Following one month of administration of Urolithin A (UA), we observed significant restoration of the abnormal protein network within the aBLA. UA treatment also attenuated the disorganized firings of the aBLA-vCA1 pathway, leading to an improvement in social ability. Conclusions: The aBLA-vCA1 circuit is a vulnerable pathway in response to Aß accumulation during the progression of AD and plays a crucial role in Aß-induced social anxiety. Targeting the aBLA-vCA1 circuit and UA administration are both effective strategies for improving the Aß-impaired social ability.
Subject(s)
Amyloid beta-Peptides , Basolateral Nuclear Complex , CA1 Region, Hippocampal , Coumarins , Mice, Transgenic , Animals , Mice , Amyloid beta-Peptides/metabolism , CA1 Region, Hippocampal/metabolism , CA1 Region, Hippocampal/drug effects , Basolateral Nuclear Complex/metabolism , Basolateral Nuclear Complex/drug effects , Coumarins/pharmacology , Alzheimer Disease/metabolism , Male , Social Behavior , Disease Models, Animal , Anxiety/metabolism , Social Interaction/drug effects , Neural Pathways/drug effects , OptogeneticsABSTRACT
Chronic restraint stress induces cognitive abnormalities through changes in synapses and oxidant levels in the amygdala and hippocampus. Given the neuroprotective effects of fruit of Terminalia chebula (Halileh) in different experimental models, the present investigation aimed to address whether Terminalia chebula is able to reduce chronic restraint stress-induced behavioral, synaptic and oxidant markers in the rat model. Thirty-two male Wistar rats were randomly divided into four groups as follows: control (did not receive any treatment and were not exposed to stress), stress (restraint stress for 2â¯h a day for 14 consecutive days), Terminalia chebula (received 200â¯mg/kg hydroalcoholic extract of Terminalia chebula), and stress + Terminalia chebula groups (received 200â¯mg/kg extract of Terminalia chebula twenty minutes before stress) (n = 8 in each group). We used the shuttle box test to assess learning and memory, Golgi-Cox staining to examine dendritic spine density in the dentate gyrus region of the hippocampus and the basolateral and central nuclei of the amygdala, and total antioxidant capacity (TAC) and total oxidant status (TOS) in the brain. The shuttle box test results demonstrated that Terminalia chebula treatment had a profound positive effect on memory parameters, including step-through latency (STL) and time spent in the dark room, when compared to the stress group. Daily oral treatment with Terminalia chebula effectively suppressed the loss of neural spine density in the dentate gyrus region of the hippocampus and the basolateral and central nuclei of the amygdala caused by chronic restraint stress, as demonstrated by Golgi-Cox staining. Additionally, the results indicate that Terminalia chebula significantly reduced the TOS and increased TAC in the brain compared to the stress group. In conclusion, our results suggest that Terminalia chebula improved memory impairment and synaptic loss in the dentate gyrus of the hippocampus and the basolateral and central nuclei of the amygdala induced by restraint stress via inhibiting oxidative damage.
Subject(s)
Dentate Gyrus , Memory Disorders , Oxidative Stress , Plant Extracts , Rats, Wistar , Restraint, Physical , Stress, Psychological , Terminalia , Animals , Terminalia/chemistry , Male , Stress, Psychological/metabolism , Rats , Oxidative Stress/drug effects , Oxidative Stress/physiology , Dentate Gyrus/metabolism , Plant Extracts/pharmacology , Synapses/drug effects , Synapses/metabolism , Synapses/pathology , Hippocampus/metabolism , Hippocampus/pathology , Hippocampus/drug effects , Basolateral Nuclear Complex/metabolism , Basolateral Nuclear Complex/drug effects , Central Amygdaloid Nucleus/metabolism , Central Amygdaloid Nucleus/drug effects , Neuroprotective Agents/pharmacology , Dendritic Spines/drug effects , Amygdala/metabolismABSTRACT
Growing evidence indicates a critical role of astrocytes in learning and memory. However, little is known about the role of basolateral amygdala complex (BLA-C) astrocytes in contextual fear conditioning (CFC), a paradigm relevant to understand and generate treatments for fear- and anxiety-related disorders. To get insights on the involvement of BLA-C astrocytes in fear memory, fluorocitrate (FLC), a reversible astroglial metabolic inhibitor, was applied at critical moments of the memory processing in order to target the acquisition, consolidation, retrieval and reconsolidation process of the fear memory. Adult Wistar male rats were bilaterally cannulated in BLA-C. Ten days later they were infused with different doses of FLC (0.5 or 1 nmol/0.5 µl) or saline before or after CFC and before or after retrieval. FLC impaired fear memory expression when administered before and shortly after CFC, but not one hour later. Infusion of FLC prior and after retrieval did not affect the memory. Our findings suggest that BLA-C astrocytes are critically involved in the acquisition/early consolidation of fear memory but not in the retrieval and reconsolidation. Furthermore, the extinction process was presumably not affected (considering that peri-retrieval administration could also affect this process).
Subject(s)
Astrocytes , Basolateral Nuclear Complex , Fear , Memory , Rats, Wistar , Animals , Fear/physiology , Fear/drug effects , Astrocytes/drug effects , Astrocytes/physiology , Male , Basolateral Nuclear Complex/drug effects , Basolateral Nuclear Complex/physiology , Rats , Memory/physiology , Memory/drug effects , Citrates/pharmacology , Conditioning, Classical/drug effects , Conditioning, Classical/physiology , Memory Consolidation/physiology , Memory Consolidation/drug effects , Amygdala/drug effects , Amygdala/physiology , Extinction, Psychological/drug effects , Extinction, Psychological/physiologyABSTRACT
Acetylcholine (ACh) is released from basal forebrain cholinergic neurons in response to salient stimuli and engages brain states supporting attention and memory. These high ACh states are associated with theta oscillations, which synchronize neuronal ensembles. Theta oscillations in the basolateral amygdala (BLA) in both humans and rodents have been shown to underlie emotional memory, yet their mechanism remains unclear. Here, using brain slice electrophysiology in male and female mice, we show large ACh stimuli evoke prolonged theta oscillations in BLA local field potentials that depend upon M3 muscarinic receptor activation of cholecystokinin (CCK) interneurons (INs) without the need for external glutamate signaling. Somatostatin (SOM) INs inhibit CCK INs and are themselves inhibited by ACh, providing a functional SOMâCCK IN circuit connection gating BLA theta. Parvalbumin (PV) INs, which can drive BLA oscillations in baseline states, are not involved in the generation of ACh-induced theta, highlighting that ACh induces a cellular switch in the control of BLA oscillatory activity and establishes an internally BLA-driven theta oscillation through CCK INs. Theta activity is more readily evoked in BLA over the cortex or hippocampus, suggesting preferential activation of the BLA during high ACh states. These data reveal a SOMâCCK IN circuit in the BLA that gates internal theta oscillations and suggest a mechanism by which salient stimuli acting through ACh switch the BLA into a network state enabling emotional memory.
Subject(s)
Acetylcholine , Cholecystokinin , Mice, Inbred C57BL , Theta Rhythm , Theta Rhythm/drug effects , Theta Rhythm/physiology , Animals , Male , Mice , Female , Acetylcholine/pharmacology , Acetylcholine/metabolism , Cholecystokinin/pharmacology , Cholecystokinin/metabolism , Interneurons/physiology , Interneurons/drug effects , Somatostatin/metabolism , Somatostatin/pharmacology , Amygdala/physiology , Amygdala/drug effects , Basolateral Nuclear Complex/physiology , Basolateral Nuclear Complex/drug effects , Nerve Net/physiology , Nerve Net/drug effects , Receptor, Muscarinic M3/physiology , Receptor, Muscarinic M3/metabolism , Parvalbumins/metabolismABSTRACT
Remote memory usually decreases over time, whereas remote drug-cue associated memory exhibits enhancement, increasing the risk of relapse during abstinence. Memory system consolidation is a prerequisite for remote memory formation, but neurobiological underpinnings of the role of consolidation in the enhancement of remote drug memory are unclear. Here, we found that remote cocaine-cue associated memory was enhanced in rats that underwent self-administration training, together with a progressive increase in the response of prelimbic cortex (PrL) CaMKII neurons to cues. System consolidation was required for the enhancement of remote cocaine memory through PrL CaMKII neurons during the early period post-training. Furthermore, dendritic spine maturation in the PrL relied on the basolateral amygdala (BLA) input during the early period of consolidation, contributing to remote memory enhancement. These findings indicate that memory consolidation drives the enhancement of remote cocaine memory through a time-dependent increase in activity and maturation of PrL CaMKII neurons receiving a sustained BLA input.
Subject(s)
Basolateral Nuclear Complex , Cocaine , Memory Consolidation , Neurons , Prefrontal Cortex , Animals , Memory Consolidation/drug effects , Memory Consolidation/physiology , Cocaine/pharmacology , Male , Rats , Prefrontal Cortex/drug effects , Prefrontal Cortex/metabolism , Prefrontal Cortex/physiology , Basolateral Nuclear Complex/drug effects , Basolateral Nuclear Complex/metabolism , Neurons/metabolism , Neurons/drug effects , Memory, Long-Term/drug effects , Memory, Long-Term/physiology , Cues , Rats, Sprague-Dawley , Calcium-Calmodulin-Dependent Protein Kinase Type 2/metabolism , Self Administration , Dendritic Spines/drug effects , Dendritic Spines/metabolism , Dendritic Spines/physiology , Cocaine-Related Disorders/metabolism , Cocaine-Related Disorders/physiopathology , Memory/drug effects , Memory/physiologyABSTRACT
Chronic alcohol exposure leads to a neuroinflammatory response involving activation of the nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome and proinflammatory cytokine production. Acute ethanol (EtOH) exposure activates GABAergic synapses in the central and basolateral amygdala (BLA) ex vivo, but whether this rapid modulation of synaptic inhibition is because of an acute inflammatory response and alters anxiety-like behavior in male and female animals is not known. Here, we tested the hypotheses that acute EtOH facilitates inhibitory synaptic transmission in the BLA by activating the NLRP3 inflammasome-dependent acute inflammatory response, that the alcohol-induced increase in inhibition is cell type and sex dependent, and that acute EtOH in the BLA reduces anxiety-like behavior. Acute EtOH application at a binge-like concentration (22-44 mm) stimulated synaptic GABA release from putative parvalbumin (PV) interneurons onto BLA principal neurons in ex vivo brain slices from male, but not female, rats. The EtOH facilitation of synaptic inhibition was blocked by antagonists of the Toll-like receptor 4 (TLR4), the NLRP3 inflammasome, and interleukin-1 receptors, suggesting it was mediated by a rapid local neuroinflammatory response in the BLA. In vivo, bilateral injection of EtOH directly into the BLA produced an acute concentration-dependent reduction in anxiety-like behavior in male but not female rats. These findings demonstrate that acute EtOH in the BLA regulates anxiety-like behavior in a sex-dependent manner and suggest that this effect is associated with presynaptic facilitation of parvalbumin-expressing interneuron inputs to BLA principal neurons via a local NLRP3 inflammasome-dependent neuroimmune response.SIGNIFICANCE STATEMENT Chronic alcohol exposure produces a neuroinflammatory response, which contributes to alcohol-associated pathologies. Acute alcohol administration increases inhibitory synaptic signaling in the brain, but the mechanism for the rapid alcohol facilitation of inhibitory circuits is unknown. We found that acute ethanol at binge-like concentrations in the basolateral amygdala (BLA) facilitates GABA release from parvalbumin-expressing (PV) interneuron synapses onto principal neurons in ex vivo brain slices from male rats and that intra-BLA ethanol reduces anxiety-like behavior in vivo in male rats, but not female rats. The ethanol (EtOH) facilitation of inhibition in the BLA is mediated by Toll-like receptor 4 (TLR4) and nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome activation and proinflammatory IL-1ß signaling, which suggests a rapid NLRP3 inflammasome-dependent neuroimmune cascade that plays a critical role in acute alcohol intoxication.
Subject(s)
Anxiety , Basolateral Nuclear Complex , Ethanol , Animals , Female , Male , Rats , Anxiety/chemically induced , Anxiety/metabolism , Basolateral Nuclear Complex/drug effects , Basolateral Nuclear Complex/metabolism , Ethanol/toxicity , gamma-Aminobutyric Acid/metabolism , Inflammasomes/metabolism , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , Nucleotides/metabolism , Nucleotides/pharmacology , Parvalbumins/metabolism , Toll-Like Receptor 4/metabolismABSTRACT
RATIONALE: The development and progression of alcohol use disorder (AUD) are widely viewed as maladaptive neuroplasticity. The transmembrane alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR) regulatory protein γ8 (TARP γ-8) is a molecular mechanism of neuroplasticity that has not been evaluated in AUD or other addictions. OBJECTIVE: To address this gap in knowledge, we evaluated the mechanistic role of TARP γ-8 bound AMPAR activity in the basolateral amygdala (BLA) and ventral hippocampus (vHPC) in the positive reinforcing effects of alcohol, which drive repetitive alcohol use throughout the course of AUD, in male C57BL/6 J mice. These brain regions were selected because they exhibit high levels of TARP γ-8 expression and send glutamate projections to the nucleus accumbens (NAc), which is a key nucleus in the brain reward pathway. METHODS AND RESULTS: Site-specific pharmacological inhibition of AMPARs bound to TARP γ-8 in the BLA via bilateral infusion of the selective negative modulator JNJ-55511118 (0-2 µg/µl/side) significantly decreased operant alcohol self-administration with no effect on sucrose self-administration in behavior-matched controls. Temporal analysis showed that reductions in alcohol-reinforced response rate occurred > 25 min after the onset of responding, consistent with a blunting of the positive reinforcing effects of alcohol in the absence of nonspecific behavioral effects. In contrast, inhibition of TARP γ-8 bound AMPARs in the vHPC selectively decreased sucrose self-administration with no effect on alcohol. CONCLUSIONS: This study reveals a novel brain region-specific role of TARP γ-8 bound AMPARs as a molecular mechanism of the positive reinforcing effects of alcohol and non-drug rewards.
Subject(s)
Alcoholism , Basolateral Nuclear Complex , Calcium Channels , Ethanol , Hippocampus , Receptors, AMPA , Sucrose , Animals , Male , Mice , Alcoholism/etiology , Alcoholism/metabolism , Basolateral Nuclear Complex/drug effects , Basolateral Nuclear Complex/metabolism , Calcium Channels/metabolism , Ethanol/administration & dosage , Ethanol/pharmacology , Glutamic Acid/metabolism , Hippocampus/drug effects , Hippocampus/metabolism , Locomotion/drug effects , Mice, Inbred C57BL , Neuronal Plasticity/drug effects , Nucleus Accumbens/metabolism , Receptors, AMPA/antagonists & inhibitors , Receptors, AMPA/metabolism , Reinforcement, Psychology , Reward , Sucrose/administration & dosage , Sucrose/pharmacologyABSTRACT
Noradrenergic activation of the basolateral amygdala (BLA) by emotional arousal enhances different forms of recognition memory via functional interactions with the insular cortex (IC). Human neuroimaging studies have revealed that the anterior IC (aIC), as part of the salience network, is dynamically regulated during arousing situations. Emotional stimulation first rapidly increases aIC activity but suppresses it in a delayed fashion. Here, we investigated in male Sprague-Dawley rats whether the BLA influence on recognition memory is associated with an increase or suppression of aIC activity during the postlearning consolidation period. We first employed anterograde and retrograde viral tracing and found that the BLA sends dense monosynaptic projections to the aIC. Memory-enhancing norepinephrine administration into the BLA following an object training experience suppressed aIC activity 1 h later, as determined by a reduced expression of the phosphorylated form of the transcription factor cAMP response element-binding (pCREB) protein and neuronal activity marker c-Fos. In contrast, the number of perisomatic γ-aminobutyric acid (GABA)ergic inhibitory synapses per pCREB-positive neuron was significantly increased, suggesting a dynamic up-regulation of GABAergic tone. In support of this possibility, pharmacological inhibition of aIC activity with a GABAergic agonist during consolidation enhanced object recognition memory. Norepinephrine administration into the BLA did not affect neuronal activity within the posterior IC, which receives sparse innervation from the BLA. The evidence that noradrenergic activation of the BLA enhances the consolidation of object recognition memory via a mechanism involving a suppression of aIC activity provides insight into the broader brain network dynamics underlying emotional regulation of memory.
Subject(s)
Basolateral Nuclear Complex , Emotions , Insular Cortex , Neural Inhibition , Recognition, Psychology , Visual Perception , Animals , Arousal , Basolateral Nuclear Complex/drug effects , Basolateral Nuclear Complex/physiology , Cyclic AMP Response Element-Binding Protein/metabolism , Emotions/drug effects , Emotions/physiology , GABA Agonists/pharmacology , Insular Cortex/drug effects , Insular Cortex/physiology , Male , Neural Inhibition/drug effects , Neural Inhibition/physiology , Norepinephrine/administration & dosage , Norepinephrine/pharmacology , Rats , Rats, Sprague-Dawley , Recognition, Psychology/drug effects , Recognition, Psychology/physiology , Visual Perception/physiologyABSTRACT
On the basis of amyloid ß (Aß) peptides as triggers in atrophy of structures in the limbic system, here we postulated that Aß1-42-induced intracellular Zn2+ toxicity in the basolateral amygdala contributes to conditioned fear memory. Aß1-42 increased intracellular Zn2+ level in the amygdala after local injection of Aß1-42 into the basolateral amygdala, resulting in conditioned fear memory deficit via attenuated LTP at perforant pathway-basolateral amygdala synapses. Co-injection of isoproterenol, a beta-adrenergic receptor agonist, reduced Aß1-42-mediated increase in intracellular Zn2+, resulting in rescue of the memory deficit and attenuated LTP. The present study suggests that beta-adrenergic activity induced by isoproterenol in the basolateral amygdala rescues the impairment of conditioned fear memory by Aß1-42. The rescuing effect may be linked with reducing Aß1-42-induced intracellular Zn2+ toxicity. Furthermore, Aß1-42 injection into the basolateral amygdala also attenuated LTP at perforant pathway-dentate granule cell synapses, while co-injection of isoproterenol rescued it, suggesting that Aß1-42 toxicity in the basolateral amygdala also affects hippocampus-dependent memory. It is likely that beta-adrenergic receptor activation in the basolateral amygdala rescues the limbic system exposed to Aß1-42 toxicity.
Subject(s)
Amyloid beta-Peptides/toxicity , Basolateral Nuclear Complex/drug effects , Basolateral Nuclear Complex/metabolism , Isoproterenol/pharmacology , Zinc/metabolism , Animals , Conditioning, Classical , Fear , Male , Memory/drug effects , Memory Disorders/chemically induced , Memory Disorders/metabolism , Neurons/metabolism , Rats , Rats, WistarABSTRACT
Drug-related memory can be transiently destabilized by memory retrieval, after which memories are reconsolidated. Neurons in the basolateral amygdala (BLA) that are activated by emotional information may be one of the key mechanisms underlying this destabilization. However, the specific neural circuits underlying this destabilization process remain unknown. Because BLA receives noradrenergic inputs from the nucleus tractus solitarius (NTS) and locus coeruleus (LC), we studied the role of afferent projections into the BLA in the destabilization of morphine self-administration memory in rats. We first showed that morphine (unconditioned stimulus, US) + morphine-associated conditioned stimuli (CS) exposure, rather than CS exposure alone, destabilized morphine self-administration memory. Then, we measured projection-specific activation after the US + CS or CS retrieval test using c-fos (activity marker)-labeling in projection areas. Compared with CS exposure, we found that US + CS exposure induced more neuronal activation in the BLA and NTS but not in the LC. Next, we determined the effects of chemogenetic inactivation or activation of NTS or LC projections to BLA (NTS â BLA or LC â BLA) on this destabilization. We found that NTS â BLA, but not LC â BLA inactivation during memory retrieval, prevented memory destabilization induced by US + CS exposure. Furthermore, NTS â BLA, but not LC â BLA activation during CS retrieval induced destabilization. Thus, our results identify a specific neural circuit underlying the transformation of a stable opiate-associated memory into an unstable memory and subsequently guide reconsolidation.