Stress-induced visceral pain in female rats is associated with epigenetic remodeling in the central nucleus of the amygdala.
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ABSTRACT:
SUBMITTER: Louwies T
PROVIDER: S-EPMC8456109 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Neuropathic pain is a major clinic probelm as it is very difficult to treat and mechanism remain unknown. Here, we investigated the differential expression of proteins in the central nuecleus of amygdala (CeA) in neuropathic pain moldel spinal nerve transection (SNT)in rats. CeA was excised from naive, sham, SNTmodels at days 3, 7, 14 and 21 rats. The aim was to quatify the differential proteins in CeA including memebrane proteins. We used gel- and mass spectrometry- based proteomics. For gel-proteomics, total tissue lysate proteins were separated by 2D-PAGE. The 2D gels from different SNT time points against Sham and control rats were compared using Progenesis SameSpot software. The spots with fold change greater then 2 excised for the proteins IDs by LC-MS/MS. Protein spots were digested using trypsin. Extracted peptides were injected on the nano C18 column and measured by a LTQ Orbitrap XL or a LTQ Orbitrap Velos mass spectrometers. For the identification of membrane proteins in CeA, we used 1-SDS-PAGE and cut the gel region of MW 80 kDa and higher for nano-LC-MS/MS analysis. We also quantified membrane proteins by utilising triplex stabel isotope dimethyl labelling at the peptide level. Sham, control and day 3, 7 and 21 after SNT surgery rats CeA membrane proteins were purified and digested by trypsin and labelled with "light", "medium" and "heavy" dimethyl labelling reagents. The resulting peptides were analysed by a nano LC connected to the Q Exactive mass spectrometer. Quantification of peptide was processed using Proteome Discoverer 1.3.
2020-02-21 | PXD017473 | Pride
Project description:BackgroundStress exacerbates many chronic pain syndromes including irritable bowel syndrome (IBS). Among these patient populations, many suffer from comorbid or chronic overlapping pain conditions and are predominantly female. Nevertheless, basic studies investigating chronic psychological stress-induced changes in pain sensitivity have been mostly carried out in male rodents. Our laboratory developed a model of comorbid pain hypersensitivity (CPH) (stress in the presence of preexisting orofacial pain inducing chronic visceral pain hypersensitivity that significantly outlasts transient stress-induced pain hypersensitivity (SIH)) facilitating the study of pain associated with IBS. Since CPH and SIH are phenotypically similar until SIH resolves and CPH persists, it is unclear if underlying mechanisms are similar.MethodsIn the present study, the visceromotor response (VMR) to colorectal distention was recorded in the SIH and CPH models in intact females and ovariectomized rats plus estradiol replacement (OVx + E2). Over several months, rats were determined to be susceptible or resilient to stress and the role of peripheral corticotrophin-releasing factor (CRF) underlying in the pain hypersensitivity was examined.Key resultsStress alone induced transient (3-4 weeks) visceral hypersensitivity, though some rats were resilient. Comorbid conditions increased susceptibility to stress prolonging hypersensitivity beyond 13 weeks. Both models had robust peripheral components; hypersensitivity was attenuated by the CRF receptor antagonist astressin and the mast cell stabilizer disodium cromoglycate (DSCG). However, DSCG was less effective in the CPH model compared to the SIH model.Conclusions and inferencesThe data indicate many similarities but some differences in mechanisms contributing to comorbid pain conditions compared to transient stress-induced pain.
| S-EPMC7319894 | biostudies-literature
Project description:The central medial nucleus (CM), a prominent cell group of the intralaminar nuclei (ILN) of the thalamus, and the ventrolateral periaqueductal gray matter (vlPAG) are two major components of the medial pain system. Whether vlPAG and CM are input sources of nociceptive information to the basolateral amygdala (BLA) and whether they are involved in neuropathic pain regulation remain unclear. Clarifying the hierarchical organization of these subcortical nuclei (vlPAG, CM, and BLA) can enhance our understanding on the neural circuits for pain regulation. Behavioral test results showed that a CM lesion made by kainic acid (KA) injection could effectively alleviate mechanical hyperalgesia 4, 6, and 8 days after spared nerve injury (SNI) surgery, with the symptoms returning after 10 days. Morphological studies revealed that: (1) the CM received afferents from vlPAG and sent efferents to BLA, indicating that an indirect vlPAG-CM-BLA pathway exists; (2) such CM-BLA projections were primarily excitatory glutamatergic neurons as revealed by fluorescence in situ hybridization; (3) the fibers originated from the CM-formed close contacts with both excitatory and inhibitory neurons in the BLA; and (4) BLA-projecting CM neurons expressed Fos induced by SNI and formed close contacts with fibers from vlPAG, suggesting that the vlPAG-CM-BLA indirect pathway was activated in neuropathic pain conditions. Finally, the vlPAG-CM-BLA indirect pathway was further confirmed using anterograde and monosynaptic virus tracing investigation. In summary, our present results provide behavioral and morphological evidence that the indirect vlPAG-CM-BLA pathway might be a novel pain pathway involved in neuropathic pain regulation.
| S-EPMC7394700 | biostudies-literature
Project description:While comorbid pain in depression (CP) occurs at a high rate worldwide, the neural connections underlying the core symptoms of CP have yet to be elucidated. Here, we define a pathway whereby GABAergic neurons from the central nucleus of the amygdala (GABACeA) project to glutamatergic neurons in the parafascicular nucleus (GluPF). These GluPF neurons relay directly to neurons in the second somatosensory cortex (S2), a well-known area involved in pain signal processing. Enhanced inhibition of the GABACeA?GluPF?S2 pathway is found in mice exhibiting CP symptoms. Reversing this pathway using chemogenetic or optogenetic approaches alleviates CP symptoms. Together, the current study demonstrates the putative importance of the GABACeA?GluPF?S2 pathway in controlling at least some aspects of CP.
| S-EPMC7020652 | biostudies-literature
Project description:AimsBasolateral amygdala (BLA), as a center for stress responses and emotional regulation, is involved in visceral hypersensitivity of irritable bowel syndrome (IBS) induced by stress. In the present study, we aimed to investigate the role of EphB2 receptor (EphB2) in BLA and explore the underlying mechanisms in this process.MethodsVisceral hypersensitivity was induced by water avoidance stress (WAS). Elevated plus maze test, forced swimming test, and sucrose preference test were applied to assess anxiety- and depression-like behaviors. Ibotenic acid or lentivirus was used to inactivate BLA in either the induction or maintenance stage of visceral hypersensitivity. The expression of protein was determined by quantitative PCR, immunofluorescence, and western blot.ResultsEphB2 expression was increased in BLA in WAS rats. Inactivation of BLA or downregulation of EphB2 in BLA failed to induce visceral hypersensitivity as well as anxiety-like behaviors. However, during the maintenance stage of visceral pain, visceral hypersensitivity was only partially relieved but anxiety-like behaviors were abolished by inactivation of BLA or downregulation of EphB2 in BLA. Chronic WAS increased the expression of EphB2, N-methyl-D-aspartate receptors (NMDARs), and postsynaptic density protein (PSD95) in BLA. Downregulation of EphB2 in BLA reduced NMDARs and PSD95 expression in WAS rats. However, activation of NMDARs after the knockdown of EphB2 expression still triggered visceral hypersensitivity and anxiety-like behaviors.ConclusionsTaken together, the results suggest that EphB2 in BLA plays an essential role in inducing visceral hypersensitivity. In the maintenance stage, the involvement of EphB2 is crucial but not sufficient. The increase in EphB2 induced by WAS may enhance synaptic plasticity in BLA through upregulating NMDARs, which results in IBS-like symptoms. These findings may give insight into the treatment of IBS and related psychological distress.
| S-EPMC10865153 | biostudies-literature
Project description:The objective of this study was to determine changes in gene expression within the extended amygdala following binge-like drinking by alcohol-preferring (P) rats. Adult male P rats were given 1-hr access to 15 and 30% ethanol (EtOH) three times daily for 8 weeks. Rats (n = 10/time point for EtOH and n = 6/time point for water) were killed by decapitation 1, 6 and 24 hr after the last drinking episode. Brains were extracted and rapidly frozen in isopentane in dry ice. RNA was prepared from individual micropunch samples of the nucleus accumbens shell (ACB-sh) and central nucleus of the amygada (CeA); microarray analyses were conducted with Affymetrix Rat 230.2 chips. EtOH intakes were 1.5-2 g/kg/session. Because too few genes changed at the individual time points, an overall effect, comparing the water and EtOH groups, was determined. In the ACB-sh and CeA, there were 276 and 402 probe sets for named genes, respectively, that were different between the two groups. There were 1.5- to 3.5- fold more genes up-regulated than down-regulated in both regions, with most differences between 1.1- to 1.2-fold. Although there were several significant Biological Processes categories in common between the 2 regions (e.g., synaptic transmission, neurite development), there were few genes in common between the two regions that differed between the EtOH and water groups. Overall, the results suggest that chronic binge-like alcohol drinking by P rats produces changes in the expression of genes that could alter neuronal function by different mechanisms in the ACB-sh and CeA. 17 samples of control and 31 samples of treatment for each brain region
2009-12-30 | E-GEOD-15407 | biostudies-arrayexpress
Project description:As one of the thalamic midline nuclei, the thalamic paraventricular nucleus (PVT) is considered to be an important signal integration site for many descending and ascending pathways that modulate a variety of behaviors, including feeding, emotions, and drug-seeking. A recent study has demonstrated that the PVT is implicated in the acute visceral pain response, but it is unclear whether the PVT plays a critical role in the central processing of chronic pain. Here, we report that the neurons in the posterior portion of the PVT (pPVT) and their downstream pathway are involved in descending nociceptive facilitation regarding the development of neuropathic pain conditions in male rats. Lesions or inhibition of pPVT neurons alleviated mechanical allodynia induced by spared nerve injury (SNI). The excitability of pPVT-central amygdala (CeA) projection neurons was significantly increased in SNI rats. Importantly, selective optogenetic activation of the pPVT-CeA pathway induced obvious mechanical hypersensitivity in naive rats. In addition, we used rabies virus (RV)-based and cell-type-specific retrograde transsynaptic tracing techniques to define a novel neuronal circuit in which glutamatergic neurons in the vlPAG were the target of the pPVT-CeA descending facilitation pathway. Our data suggest that this pPVTGlu+-CeA-vlPAGGlu+ circuit mediates central mechanisms of descending pain facilitation underlying persistent pain conditions.SIGNIFICANCE STATEMENT Studies have shown that the interactions between the posterior portion of the thalamic paraventricular nucleus (pPVT) and central amygdala (CeA) play a critical role in pain-related emotional regulation. However, most reports have associated this circuit with fear and anxiety behaviors. Here, an integrative approach of behavioral tests, electrophysiology, and immunohistochemistry was used to advance the novel concept that the pPVT-CeA pathway activation facilitates neuropathic pain processing. Using rabies virus (RV)-based and cell-type-specific retrograde transsynaptic tracing techniques, we found that glutamatergic neurons in the vlPAG were the target of the pPVT-CeA pathway. Thus, this study indicates the involvement of a pPVTGlu+-CeA-vlPAGGlu+ pathway in a descending facilitatory mechanism underlying neuropathic pain.
| S-EPMC7548696 | biostudies-literature
Project description:Objective:The amygdala structural and functional abnormalities have been implicated in numerous neuropsychiatric and neurodevelopmental disorders. Given the important role of the amygdala in stress responses and the susceptibility of the females to adolescent stress, the present study investigated the beneficial effects of Spirulina platensis microalgae (SP) as a neuroprotective supplement against adolescent stress-induced oxidative stress, brain-derived neurotrophic factor (BDNF) alterations, molecular and morphological remodeling in the basolateral amygdala (BLA) of adult female rats. Methods:During the adolescent period (PNDs 30-40) rats were subjected to restraint stress (2 h/day for 10 days). Then, the animals were subjected to 15 days treatment (PNDs 41-55) with SP (200 mg/kg/day) followed by biochemical (BDNF and stress oxidative markers), molecular (BDNF and its receptor tropomyosin receptor kinase B [TrkB] mRNA expression), and morphological (dendritic length and spines) assessments in the BLA. Results:The study revealed that adolescent stress decreased BDNF levels and reduced apical dendritic length and branch points of pyramidal neurons in the BLA. In addition, chronic stress significantly increased oxidative stress parameters and decreased BDNF and TrkB mRNA expression in the BLA. Treatment with SP alleviated both biochemical, molecular, and neuroanatomical deficits that induced by adolescent stress. Conclusion:Our findings provide important evidence that SP as a non-pharmacological intervention during adolescent period can protect against chronic stress-induced neuroanatomical biochemical, and molecular deficits in adulthood, and thus, reduce stress-related disorders.
| S-EPMC7090200 | biostudies-literature
Project description:Male rats escalate intravenous self-administration of entactogen psychostimulants, 3,4-methylenedioxymethcathinone (methylone) and 3,4-methylenedioxymethamphetamine (MDMA) under extended access conditions, as with typical psychostimulants. Here, we investigated whether female rats escalate self-administration of methylone, 3,4-methylenedioxypentedrone (pentylone), and MDMA and then studied consequences of MDMA and pentylone self-administration on GABAA receptor and kappa opioid receptor (KOR) signaling in the central nucleus of the amygdala (CeA), a brain area critically dysregulated by extended access self-administration of alcohol or cocaine. Adult female Wistar rats were trained to self-administer methylone, pentylone, MDMA (0.5 mg/kg/infusion), or saline-vehicle using a fixed-ratio 1 response contingency in 6-h sessions (long-access: LgA) followed by progressive ratio (PR) dose-response testing. The effects of pentylone-LgA, MDMA-LgA and saline on basal GABAergic transmission (miniature post-synaptic inhibitory currents, mIPSCs) and the modulatory role of KOR at CeA GABAergic synapses were determined in acute brain slices using whole-cell patch-clamp. Methylone-LgA and pentylone-LgA rats similarly escalated their drug intake (both obtained more infusions compared to MDMA-LgA rats), however, pentylone-LgA rats reached higher breakpoints in PR tests. At the cellular level, baseline CeA GABA transmission was markedly elevated in pentylone-LgA and MDMA-LgA rats compared to saline-vehicle. Specifically, pentylone-LgA was associated with increased CeA mIPSC frequency (GABA release) and amplitude (post-synaptic GABAA receptor function), while mIPSC amplitudes (but not frequency) was larger in MDMA-LgA rats compared to saline rats. In addition, pentylone-LgA and MDMA-LgA profoundly disrupted CeA KOR signaling such as both KOR agonism (1 mM U50488) and KOR antagonism (200 nM nor-binaltorphimine) decreased mIPSC frequency suggesting recruitment of non-canonical KOR signaling pathways. This study confirms escalated self-administration of entactogen psychostimulants under LgA conditions in female rats which is accompanied by increased CeA GABAergic inhibition and altered KOR signaling. Collectively, our study suggests that CeA GABA and KOR mechanisms play a critical role in entactogen self-administration like those observed with escalation of alcohol or cocaine self-administration.
| S-EPMC8716434 | biostudies-literature
Project description:The objective of this study was to determine changes in gene expression within the extended amygdala following binge-like drinking by alcohol-preferring (P) rats. Adult male P rats were given 1-hr access to 15 and 30% ethanol (EtOH) three times daily for 8 weeks. Rats (n = 10/time point for EtOH and n = 6/time point for water) were killed by decapitation 1, 6 and 24 hr after the last drinking episode. Brains were extracted and rapidly frozen in isopentane in dry ice. RNA was prepared from individual micropunch samples of the nucleus accumbens shell (ACB-sh) and central nucleus of the amygada (CeA); microarray analyses were conducted with Affymetrix Rat 230.2 chips. EtOH intakes were 1.5-2 g/kg/session. Because too few genes changed at the individual time points, an overall effect, comparing the water and EtOH groups, was determined. In the ACB-sh and CeA, there were 276 and 402 probe sets for named genes, respectively, that were different between the two groups. There were 1.5- to 3.5- fold more genes up-regulated than down-regulated in both regions, with most differences between 1.1- to 1.2-fold. Although there were several significant Biological Processes categories in common between the 2 regions (e.g., synaptic transmission, neurite development), there were few genes in common between the two regions that differed between the EtOH and water groups. Overall, the results suggest that chronic binge-like alcohol drinking by P rats produces changes in the expression of genes that could alter neuronal function by different mechanisms in the ACB-sh and CeA.
2009-12-31 | GSE15407 | GEO