RESUMO
War and crises affect mental health, social attitudes, and cultural norms, which can exacerbate the state of long-term insecurity. With decades of armed conflict, the Democratic Republic of Congo is one example, and violence has become normalized in civilian settings. In this study, we tested the effectiveness of the NETfacts health system, an integrated model of evidence-based individual trauma treatment (Narrative Exposure Therapy [NET]) and a trauma-informed community-based intervention (NETfacts). Alongside changes in mental health outcomes (posttraumatic stress disorder, depression, social disapproval, and shame) we also investigated change in attitudes, including rape myth acceptance, stigmatization of survivors of sexual violence, and skepticism about the reintegration of former combatants. To test whether the additional community intervention is superior to individual NET alone, we implemented a randomized controlled design with six villages and interviewed a sample of 1,066 community members. Our results demonstrate that the NETfacts health system in comparison with NET alone more effectively reduced rape myth acceptance and with it ongoing victimization and perpetration. Community members of the NETfacts group also presented with less stigmatizing attitudes against survivors of sexual violence. Skepticism about the reintegration of former combatants declined in both groups. NETfacts appears to have increased motivation to engage in individual treatment. Synergizing the healing effects of individual and collective trauma exposure, the NETfacts health system appears to be an effective and scalable approach to correct degrading or ignominious norms and restore functioning and mental health in postconflict communities.
Assuntos
Estupro , Delitos Sexuais , Transtornos de Estresse Pós-Traumáticos , Humanos , Estupro/psicologia , Transtornos de Estresse Pós-Traumáticos/terapia , Transtornos de Estresse Pós-Traumáticos/psicologia , ViolênciaRESUMO
BACKGROUND: Shame is an emotion reflecting an anticipated social devaluation of the self. It is strongly associated with experiences of humiliation and rejection in early life. Individuals suffering from post-traumatic stress disorder (PTSD) often struggle with shame. However, little is known about how shame contributes to the development and maintenance of PTSD symptoms in children. The present study investigated the ways childhood exposure to human-induced traumatic events promotes a coping mechanism of defeat and withdrawal facilitated by the experience of shame. We tested a dose-response relationship between lifetime experienced traumatic event types and PTSD in children using shame as a mediator. METHODS: We conducted semi-structured interviews with 33 male children who lived and worked on the streets of Bujumbura, the capital of Burundi at the time of data collection. We assessed self-reported PTSD symptom severity, lifetime traumatic event load, violence experienced on the streets and shame intensity. RESULTS: Mediation analyses revealed a significant indirect effect of lifetime traumatic events on PTSD symptom severity through shame intensity and a significant indirect effect of violence experienced on the streets on PTSD symptom severity through shame intensity. CONCLUSION: Our study suggests the mediating role of shame between traumatic experiences as well as violent experiences and PTSD symptom severity in children living on the streets. Shame in children suffering from PTSD seems to play a crucial role in the development and maintenance of PTSD symptoms.
Assuntos
Transtornos de Estresse Pós-Traumáticos , Adaptação Psicológica , Agressão , Criança , Humanos , Masculino , Vergonha , Transtornos de Estresse Pós-Traumáticos/psicologia , Violência/psicologiaRESUMO
Reduction in the expression or function of α5-subunit-containing GABAA receptors (α5GABAARs) leads to improvement in several hippocampus-dependent memory domains. However, studies thus far mostly lack anatomical specificity in terms of neuronal circuits and populations. We demonstrate that mice with a selective knockdown of α5GABAARs in CA1 pyramidal neurons (α5CA1KO mice) show improved spatial and trace fear-conditioning memory. Unexpectedly, α5CA1KO mice were comparable to controls in contextual fear-conditioning but showed an impairment in context discrimination, suggesting fine-tuning of activity in CA1 pyramidal cell dendrites through α5-mediated inhibition might be necessary for distinguishing highly similar contexts.
Assuntos
Região CA1 Hipocampal/fisiologia , Memória/fisiologia , Receptores de GABA-A/fisiologia , Animais , Condicionamento Clássico/fisiologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Teste do Labirinto Aquático de Morris/fisiologiaRESUMO
Individuals who perpetrate violence may likely perceive violence as appealing and infliction of violence to derive pleasure is termed as appetitive aggression. Individuals who were abducted as children into an armed group often experience a higher number of traumatic event types, that is traumatic load and are usually socialized in a violence-endorsing environment. This study aims to investigate the interaction between age at initial abduction with that of traumatic load, and their influence on appetitive aggression along with perpetration of violent acts by former members of an armed rebel group of both sexes. Semi-structured interviews were conducted among a target group of formerly abducted rebel-war survivors (including participants with and without combat experience) from Northern Uganda. Participants included 596 women and 570 men with N = 1,166 (Mage = 32.58, SDage = 9.76, range: 18-80 years). We conducted robust linear regression models to investigate the influence of age at initial abduction, traumatic load, combat experience, and biological sex on appetitive aggression as well as their perpetrated violent acts. Our study shows, appetitive aggression and the number of perpetrated violent acts were specifically increased in individuals who were abducted young, experienced several traumatic events in their lifetime, and with previous combat experience. For perpetrated violence men showed increased levels whereas for appetitive aggression the association was independent of biological sex. Therefore, early abducted individuals with a higher traumatic load, who have combat experience, need to be given special intervention to prevent any further violence.
Assuntos
Agressão , Conflitos Armados , Transtornos de Estresse Pós-Traumáticos , Criança , Crime , Feminino , Humanos , Masculino , Uganda , ViolênciaRESUMO
Previous experiments using genetic and pharmacological manipulations have provided strong evidence that etomidate impairs synaptic plasticity and memory by modulating α5-subunit containing GABAA receptors (α5-GABAARs). Because α5-GABAARs mediate tonic inhibition (TI) in hippocampal CA1 pyramidal cells and etomidate enhances TI, etomidate enhancement of TI in pyramidal cells has been proposed as the underlying mechanism (Martin et al., 2009). Here we tested this hypothesis by selectively removing α5-GABAARs from pyramidal neurons (CA1-pyr-α5-KO) and comparing the ability of etomidate to enhance TI and block LTP in fl-α5 (WT), global-α5-KO (gl-α5-KO), and CA1-pyr-α5-KO mice. Etomidate suppressed LTP in slices from WT and CA1-pyr-α5-KO but not gl-α5-KO mice. There was a trend toward reduced TI in both gl-α5-KO and CA1-pyr-α5-KO mice, but etomidate enhanced TI to similar levels in all genotypes. The dissociation between effects of etomidate on TI and LTP in gl-α5-KO mice indicates that increased TI in pyramidal neurons is not the mechanism by which etomidate impairs LTP and memory. Rather, the ability of etomidate to block LTP in WT and CA1-pyr-α5-KO mice, but not in gl-α5-KO mice, points toward α5-GABAARs on nonpyramidal cells as the essential effectors controlling plasticity in this in vitro model of learning and memory.
Assuntos
Etomidato/farmacologia , Hipocampo/citologia , Hipnóticos e Sedativos/farmacologia , Potenciação de Longa Duração/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Receptores de GABA-A/metabolismo , Animais , Biofísica , Estimulação Elétrica , Antagonistas de Aminoácidos Excitatórios/farmacologia , Antagonistas GABAérgicos/farmacologia , Técnicas In Vitro , Ácido Cinurênico , Potenciação de Longa Duração/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neurônios/fisiologia , Picrotoxina/farmacologia , Receptores de GABA-A/genética , Ácido gama-Aminobutírico/farmacologiaRESUMO
BACKGROUND: Parental support has been suggested to mitigate mental and physical consequences following childhood sexual abuse (CSA). However, many CSA survivors experience parental rejection post-CSA. OBJECTIVE: We aimed to understand the impact of abuse-specific parental acceptance on post-traumatic stress disorder (PTSD) and physical pain in Burundian CSA-survivors. We further assessed the significance of parental acceptance among known risk factors for predicting PTSD. METHODS, PARTICIPANTS, AND SETTINGS: Participants (N = 131, 80.9 % female, mean age 16.21 years) were recruited via primary health care centers for survivors of sexual violence which survivors approached post-CSA. Survivors reported on PTSD symptoms, daytime/nighttime pain, and adverse childhood experiences in semi-structured interviews. Parental acceptance levels were categorized (acceptance, no acceptance, no contact) for mothers and fathers separately. Kruskal-Wallis tests assessed group differences. Conditional random forests (CRF) evaluated the significance of parental acceptance in predicting PTSD symptom severity. RESULTS: No significant differences regarding PTSD symptoms and physical pain between levels of maternal acceptance were obtained. Pairwise comparisons revealed significant differences in PTSD symptom severity between paternal acceptance and no acceptance (d = 1.04) and paternal acceptance and no contact (d = 0.81). The CRF identified paternal acceptance as important variable for the prediction of PTSD symptom severity. Even though results were less conclusive, medium effect sizes hint at less pain perception within the paternal acceptance group. CONCLUSIONS: The results highlight paternal acceptance as a potential risk or protective factor regarding psychological and possibly physical well-being in the aftermath of CSA, even in the context of other known risk factors.
Assuntos
Sobreviventes Adultos de Maus-Tratos Infantis , Abuso Sexual na Infância , Dor , Transtornos de Estresse Pós-Traumáticos , Humanos , Feminino , Masculino , Transtornos de Estresse Pós-Traumáticos/psicologia , Transtornos de Estresse Pós-Traumáticos/etiologia , Adolescente , Abuso Sexual na Infância/psicologia , Sobreviventes Adultos de Maus-Tratos Infantis/psicologia , Dor/psicologia , Dor/etiologia , Adulto , Pais/psicologia , Criança , Adulto Jovem , Fatores de Risco , Experiências Adversas da Infância/estatística & dados numéricos , Experiências Adversas da Infância/psicologia , Relações Pais-Filho , Saúde MentalRESUMO
Soldiers may be exposed to traumatic stress during combat deployment and thus are at risk for developing posttraumatic stress disorder (PTSD). Genetic and epigenetic evidence suggests that PTSD is linked to forming stress-related memories. In the current study, we investigated post-deployment associations of PTSD symptoms with differential DNA methylation in a sample of Burundian soldiers returning from the African Union Mission in Somalia's war zone. We used a matched longitudinal study design to explore epigenetic changes associated with PTSD symptoms in N = 191 participants. PTSD symptoms and saliva samples were collected at 1-3 (t1) and 9-14 months (t2) after the return of the soldiers to their home base. Individuals with either worsening or improving PTSD symptoms were matched for age, stressful, traumatic and self-perpetrated events prior to the post-assessment, traumatic and violent experiences between the post- and the follow-up assessment, and violence experienced during childhood. A mixed model analysis was conducted to identify top nominally significantly differentially methylated genes, which were then used to perform a gene enrichment analysis. The linoleic acid metabolism pathway was significantly associated with post-deployment PTSD symptoms, after accounting for multiple comparisons. Linoleic acid has been linked to memory and immune related processes in previous research. Our findings suggest that differential methylation of linoleic acid pathway genes is associated with PTSD and thus may merit closer inspection as a possible mediator of resilience.
Assuntos
Militares , Transtornos de Estresse Pós-Traumáticos , Humanos , Transtornos de Estresse Pós-Traumáticos/genética , Transtornos de Estresse Pós-Traumáticos/diagnóstico , Ácido Linoleico , Estudos Longitudinais , Metilação de DNARESUMO
The aftermath of traumatization lives on in the neural and epigenetic traces creating a momentum of affliction in the psychological and social realm. Can psychotherapy reorganise these memories through changes in DNA methylation signatures? Using a randomised controlled parallel group design, we examined methylome-wide changes in saliva samples of 84 female former child soldiers from Eastern DR Congo before and six months after Narrative Exposure Therapy. Treatment predicted differentially methylated positions (DMPs) related to ALCAM, RIPOR2, AFAP1 and MOCOS. In addition, treatment associations overlapped at gene level with baseline clinical and social outcomes. Treatment related DMPs are involved in memory formation-the key agent in trauma focused treatments-and enriched for molecular pathways commonly affected by trauma related disorders. Results were partially replicated in an independent sample of 53 female former child soldiers from Northern Uganda. Our results suggest a molecular impact of psychological treatment in women with war-related childhood trauma.Trial registration: Addressing Heightened Levels of Aggression in Traumatized Offenders With Psychotherapeutic Means (ClinicalTrials.gov Identifier: NCT02992561, 14/12/2016).
Assuntos
Experiências Adversas da Infância , Metilação de DNA , Terapia Implosiva , Transtornos de Estresse Pós-Traumáticos/genética , Adolescente , Adulto , Agressão , Antígenos CD/genética , Conflitos Armados , Moléculas de Adesão Celular/genética , Moléculas de Adesão Celular Neuronais/genética , Criança , República Democrática do Congo , Feminino , Proteínas Fetais/genética , Humanos , Proteínas dos Microfilamentos/genética , Transtornos de Estresse Pós-Traumáticos/terapia , Sulfurtransferases/genéticaRESUMO
Background: Khat (Catha edulis) is a traditionally used substance in African and Arab countries that contains the amphetamine-like alkaloid cathinone. Khat use among Ethiopian students is a growing concern. This study aims to describe khat use, psychological problems, and motivation to change and to determine associated factors of khat use among students from Jimma University seeking psychological assistance. Methods: In a cross-sectional study, a sample of 717 students from Jimma University, southwestern Ethiopia, who seek assistance to reduce khat use were recruited. The study used Amharic and Afaan Oromoo language versions of common psychological instruments and employed them as part of a comprehensive tablet computer-delivered self-report assessment battery, comprising the SRQ-20, the PCL-5, the LEC-5, the AUDIT, and the SOCRATES-khat. In addition, socio-demographic, economic variables, and functioning problems due to severe mental disorders were assessed. The analysis relied on the data of the 575 included participants and used clinical cut-off values to describe this treatment-seeking sample and hierarchical regression models to determine variables associated with khat use. Results: The sample showed high khat use in the past month (M = 31.55 bundles, SD = 28.53, on M = 15.11 days, SD = 8.54); 17.0% showed highly problematic use. The sample was extremely burdened with comorbid psychiatric problems: 21.6% reported functioning problems due to past mental disorders, 60.2% scored above the cut-off for current common mental disorders, 37.9% screened positive for PTSD, and 47.1% reported hazardous alcohol use. Small to medium intercorrelations between variables were detected, and in hierarchical regression models, higher motivation to change khat use was associated with higher use of the substance. Conclusions: This study clearly shows the need to develop research instruments, screening methods, and assistance services for khat-using students at Jimma University. Study participants' high mental health burden shows the need for targeted intervention programs that go beyond brief interventions for khat use. Furthermore, the study highlights challenges for implementing such services: the barriers to utilization for females and khat users without comorbid mental health problems.
Assuntos
Catha , Transtornos Relacionados ao Uso de Substâncias , Catha/efeitos adversos , Estudos Transversais , Etiópia/epidemiologia , Humanos , Idioma , Prevalência , Estudantes , Transtornos Relacionados ao Uso de Substâncias/epidemiologia , UniversidadesRESUMO
OBJECTIVE: Brief interventions based on personalized feedback have shown promising results in reducing risky alcohol use among university students. We investigated the effects of activating deliberative (predecisional) or implemental (postdecisional) mindsets on the effectiveness of a standardized brief intervention, the ASSIST-linked Brief Intervention. This intervention comprises a personalized feedback and a decisional balance exercise. We hypothesized that participants in a deliberative mindset should show better outcomes related to risk perception and behavior than participants in an implemental mindset. METHODS: A sample of 257 students provided baseline measures on risk perception, readiness to change, and alcohol use. Of those, 64 students with risky alcohol use were randomly allocated to one of two mindset induction conditions-deliberative or implemental mindset. Thereafter, they received the ASSIST-linked Brief Intervention and completed self-report questionnaires on changes in risk perception, alcohol use, and readiness to change at post-intervention and four-week follow-up. RESULTS: In contrast to our hypotheses, the four-weeks follow-up revealed that participants in the implemental mindset consumed significantly less alcohol than participants in a deliberative mindset did. The former decreased and the latter increased their alcohol intake; resistance to the brief intervention was stronger in the latter condition. However, neither deliberative nor implemental mindset participants showed any changes in risk perceptions or in their readiness to change alcohol consumption. CONCLUSIONS: These findings suggest that mindset induction is a powerful moderator of the effects of the ASSIST-linked Brief Intervention. We argue that systematic research on mindset effects on brief intervention techniques aimed to reduce risky alcohol use is highly needed in order to identify the processes involved with commitment and resistance being the main candidates.
Assuntos
Consumo de Álcool na Faculdade , Adulto , Consumo de Bebidas Alcoólicas , Feminino , Comportamentos Relacionados com a Saúde , Educação em Saúde/métodos , Humanos , Masculino , Projetos Piloto , Inquéritos e Questionários , Adulto JovemRESUMO
The early detection of cognitive impairment or dementia is in the focus of current research as the amount of cognitively impaired individuals will rise intensely in the next decades due to aging population worldwide. Currently available diagnostic tools to detect mild cognitive impairment (MCI) or dementia are time-consuming, invasive or expensive and not suitable for wide application as required by the high number of people at risk. Thus, a fast, simple and sensitive test is urgently needed to enable an accurate detection of people with cognitive dysfunction and dementia in the earlier stages to initiate specific diagnostic and therapeutic interventions. We examined digital Clock Drawing Test (dCDT) kinematics for their clinical utility in differentiating patients with amnestic MCI (aMCI) or mild Alzheimer's dementia (mAD) from healthy controls (HCs) and compared it with the diagnostic value of the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) neuropsychological battery total score. Data of 381 participants (138 patients with aMCI, 106 patients with mAD and 137 HCs) was analyzed in the present study. All participants performed the clock drawing test (CDT) on a tablet computer and underwent the CERAD test battery and depression screening. CERAD total scores were calculated by subtest summation, excluding MMSE scores. All tablet variables (i.e. time in air, time on surface, total time, velocity, pressure, pressure/velocity relation, strokes per minute, time not painting, pen-up stroke length, pen-up/pen-down relation, and CDT score) during dCDT performance were entered in a forward stepwise logistic regression model to assess, which parameters best discriminated between aMCI or mAD and HC. Receiver operating characteristics (ROC) curves were constructed to visualize the specificity in relation to the sensitivity of dCDT variables against CERAD total scores in categorizing the diagnostic groups. dCDT variables provided a slightly better diagnostic accuracy of 81.5% for discrimination of aMCI from HCs than using CERAD total score (accuracy 77.5%). In aMCI patients with normal CDT scores, both dCDT (accuracy 78.0%) and CERAD total scores (accuracy 76.0%) were equally accurate in discriminating against HCs. Finally, in differentiating patients with mAD from healthy individuals, accuracy of both dCDT (93.0%) and CERAD total scores (92.3%) was excellent. Our findings suggest that dCDT is a suitable screening tool to identify early cognitive dysfunction. Its performance is comparable with the time-consuming established psychometric measure (CERAD test battery).
Assuntos
Doença de Alzheimer/diagnóstico , Doença de Alzheimer/psicologia , Testes Neuropsicológicos , Idoso , Estudos de Casos e Controles , Disfunção Cognitiva/diagnóstico , Disfunção Cognitiva/psicologia , Diagnóstico Diferencial , Diagnóstico Precoce , Feminino , Humanos , MasculinoRESUMO
BACKGROUND: Agents belonging to diverse chemical classes are used clinically as general anesthetics. The molecular targets mediating their actions are however still only poorly defined. Both chemical diversity and substantial differences in the clinical actions of general anesthetics suggest that general anesthetic agents may have distinct pharmacological targets. It was demonstrated previously that the immobilizing action of etomidate and propofol is completely, and the immobilizing action of isoflurane partly mediated, by beta3-containing GABAA receptors. This was determined by using the beta3(N265M) mice, which carry a point mutation known to decrease the actions of general anesthetics at recombinant GABAA receptors. In this communication, we analyzed the contribution of beta3-containing GABAA receptors to the pharmacological actions of isoflurane, etomidate and propofol by means of beta3(N265M) mice. RESULTS: Isoflurane decreased core body temperature and heart rate to a smaller degree in beta3(N265M) mice than in wild type mice, indicating a minor but significant role of beta3-containing GABAA receptors in these actions. Prolonged time intervals in the ECG and increased heart rate variability were indistinguishable between genotypes, suggesting no involvement of beta3-containing GABAA receptors. The anterograde amnesic action of propofol was indistinguishable in beta3(N265M) and wild type mice, suggesting that it is independent of beta3-containing GABAA receptors. The increase of heart rate variability and prolongation of ECG intervals by etomidate and propofol were also less pronounced in beta3(N265M) mice than in wild type mice, pointing to a limited involvement of beta3-containing GABAA receptors in these actions. The lack of etomidate- and propofol-induced immobilization in beta3(N265M) mice was also observed in congenic 129X1/SvJ and C57BL/6J backgrounds, indicating that this phenotype is stable across different backgrounds. CONCLUSION: Our results provide evidence for a defined role of beta3-containing GABAA receptors in mediating some, but not all, of the actions of general anesthetics, and confirm the multisite model of general anesthetic action. This pharmacological separation of anesthetic endpoints also suggests that subtype-selective substances with an improved side-effect profile may be developed.
Assuntos
Anestésicos Inalatórios/farmacologia , Anestésicos Intravenosos/farmacologia , Receptores de GABA-A/fisiologia , Amnésia Anterógrada/induzido quimicamente , Animais , Temperatura Corporal/efeitos dos fármacos , Eletrocardiografia , Etomidato/farmacologia , Frequência Cardíaca/efeitos dos fármacos , Resposta de Imobilidade Tônica/efeitos dos fármacos , Isoflurano/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Atividade Motora/efeitos dos fármacos , Propofol/farmacologiaRESUMO
OBJECTIVE: Past research revealed war trauma and posttraumatic stress disorder (PTSD) symptoms as potential predictors for domestic and community violence in crisis regions and among soldiers in different armed conflicts. The impact of family violence and other adversities experienced in childhood as well as of a combat-enhanced appeal for aggressive behavior (appetitive aggression) remains to be specified. METHOD: In the present study, the authors separately predicted violence against children, intimate partner violence and community violence in 381 Burundian soldiers returning from foreign deployment and living in a post- conflict region. Using path analysis, they aimed to disentangle the independent contributions and pathways of the following variables: Exposure to war trauma and childhood familial violence, PTSD and depression symptom severity, and appetitive aggression. RESULTS: Childhood familial violence had an independent effect on all contexts of violence and was the only significant predictor for violence against the soldiers' own children. Intimate partner violence was additionally predicted by depression symptom severity, while community violence was additionally predicted by PTSD symptom severity and appetitive aggression. CONCLUSIONS: Besides war-related mental ill-health and appetitive aggression, violent experiences during childhood development must not be overlooked as a factor fueling the cycle of violence in conflict regions. (PsycINFO Database Record
Assuntos
Militares/psicologia , Violência , Guerra , Adulto , Sobreviventes Adultos de Maus-Tratos Infantis/psicologia , Agressão , Depressão/psicologia , Humanos , Masculino , Escalas de Graduação Psiquiátrica , Transtornos de Estresse Pós-Traumáticos/psicologiaRESUMO
General anesthetics are among the most widely used and important therapeutic agents. The molecular targets mediating different endpoints of the anesthetic state in vivo are currently largely unknown. The analysis of mice carrying point mutations in neurotransmitter receptor subunits is a powerful tool to assess the contribution of the respective receptor subtype to the pharmacological actions of clinically used general anesthetics. We examined the involvement of beta3-containing GABA(A) receptors in the respiratory, cardiovascular, hypothermic, and sedative actions of etomidate and propofol using beta3(N265M) knock-in mice carrying etomidate- and propofol-insensitive beta3-containing GABA(A) receptors. Although the respiratory depressant action of etomidate and propofol, as determined by blood gas analysis, was almost absent in beta3(N265M) mice, the cardiac depressant and hypothermic effects, as determined by radiotelemetry, and the sedative effect, as determined by decrease of motor activity, were still present. Taken together with previous findings, our results show that both immobilization and respiratory depression are mediated by beta3-containing GABA(A) receptors, hypnosis by both beta3- and beta2-containing GABA(A) receptors, while the hypothermic, cardiac depressant, and sedative actions are largely independent of beta3-containing GABA(A) receptors.
Assuntos
Anestésicos Gerais/farmacologia , Etomidato/farmacologia , Propofol/farmacologia , Respiração/efeitos dos fármacos , Anestésicos Intravenosos/farmacologia , Animais , Gasometria , Feminino , Genótipo , Frequência Cardíaca/efeitos dos fármacos , Hipotermia/tratamento farmacológico , Camundongos , Modelos Biológicos , Oxigênio/metabolismo , Mutação Puntual , Receptores de GABA-A/genética , Fatores de TempoRESUMO
Barbiturates were introduced into medical practice in 1934. They are widely used today as general anesthetics. Although in vitro studies revealed that the activity of a variety of ligand-gated channels is modulated by barbiturates, the target(s) mediating the anesthetic actions of barbiturates in vivo are unknown. Studying pentobarbital action in beta3(N265M) mice harboring beta3-containing GABAA receptors insensitive to a variety of general anesthetic agents, we found that the immobilizing action of pentobarbital is mediated fully, and the hypnotic action is mediated in part by this receptor subtype. It was surprising that the respiratory depressant action of pentobarbital is indistinguishable between beta3(N265M) and wild-type mice and thus is mediated by other as-yet-unidentified targets. Whereas the target for the immobilizing and hypnotic actions of pentobarbital seems to be the same as for etomidate and propofol, these latter agents' respiratory depressant actions are mediated by beta3-containing GABAA receptors. Thus, in contrast to etomidate and propofol, pentobarbital can elicit respiratory depression by a beta3-independent pathway. Pentobarbital reduced heart rate and body temperature to a slightly smaller extent in beta3(N265M) mice compared with wild-type mice, indicating that these actions are largely mediated by other targets. Pentobarbital-induced increase of heart rate variability and prolongation of ECG intervals are seen in both beta3(N265M) mice and wild-type mice, suggesting that they are not dependent on beta3-containing GABAA receptors. In summary, we show a clear pharmacological dissociation of the immobilizing/hypnotic and respiratory/cardiovascular actions of pentobarbital.
Assuntos
Anestésicos/farmacologia , Pentobarbital/farmacologia , Receptores de GABA-A/fisiologia , Animais , Temperatura Corporal/efeitos dos fármacos , Eletrocardiografia/efeitos dos fármacos , Feminino , Frequência Cardíaca/efeitos dos fármacos , Camundongos , Receptores de GABA-A/efeitos dos fármacos , Reflexo/efeitos dos fármacos , Respiração/efeitos dos fármacosRESUMO
Dihydroxyacetone (Dha) kinases are a novel family of kinases with signaling and metabolic functions. Here we report the x-ray structures of the transcriptional activator DhaS and the coactivator DhaQ and characterize their function. DhaQ is a paralog of the Dha binding Dha kinase subunit; DhaS belongs to the family of TetR repressors although, unlike all known members of this family, it is a transcriptional activator. DhaQ and DhaS form a stable complex that in the presence of Dha activates transcription of the Lactococcus lactis dha operon. Dha covalently binds to DhaQ through a hemiaminal bond with a histidine and thereby induces a conformational change, which is propagated to the surface via a cantilever-like structure. DhaS binding protects an inverted repeat whose sequence is GGACACATN6ATTTGTCC and renders two GC base pairs of the operator DNA hypersensitive to DNase I cleavage. The proximal half-site of the inverted repeat partially overlaps with the predicted -35 consensus sequence of the dha promoter.