RESUMO
BACKGROUND: Advance Care Planning interventions should be evaluated as broadly as possible to gain a holistic understanding of the Advance Care Planning process. However, validated early stage outcome instruments are lacking. Therefore, the Treatment-Preference-Measure-Advance Care Planning (Treat-Me-ACP) instrument was developed and validated as part of the cluster-randomized controlled trial STADPLAN (Study on Advance Care Planning in care-dependent community-dwelling older persons) to assess the effects of Advance Care Planning interventions on patients' medical treatment preferences. METHODS: The design of Treat-Me-ACP is based on the Emanuel Medical Directive and the Life Support Preferences Questionnaires. Using a multi-stage team approach a preliminary version of the Treat-Me-ACP was developed and pre-tested. The pre-tested instrument consists of one global medical care goal-item, five hypothetical scenarios with five hypothetical treatments, and one how would you feel-item within each scenario. A total of five scenario preference scores and five treatment preference scores can be formed. This version was subsequently applied to a subsample of the STADPLAN project (n = 80) to assess patient's preferences at baseline (T0) and at 12-month follow-up (T2). The further validation steps were based on this subsample and included: (1) acceptance by using completion rate and frequencies of missing data, (2) internal consistency by using Cronbach's α to test whether it was possible to create preference scores by scenario and treatment, (3) concurrent validation examining the association between the global medical care goal-item and the preference scores and the association between the how would you feel-items and the scenario preference scores, and (4) responsiveness of the instrument to changes in preferences for life-sustaining treatments by comparing preference scores from T0 to T2 between study groups. RESULTS: Acceptance of the instrument was high. Results of concurrent validation indicate that the five scenarios represent the global medical care goal well. The preference scores showed an average tendency for decreasing preferences for life-sustaining treatments across all scales for the intervention group during study follow-up. CONCLUSIONS: The Treat-Me-ACP can be used to evaluate the dynamics of patients' medical treatment preferences in Advance Care Planning. It has been validated for care-dependent community-dwelling older persons and can be used as an additional outcome measure in evaluating the effectiveness of ACP interventions. TRIAL REGISTRATION: German Clinical Trials Register: DRKS00016886 on 04/06/2019.
Assuntos
Planejamento Antecipado de Cuidados , Assistência Terminal , Humanos , Idoso , Idoso de 80 Anos ou mais , Diretivas Antecipadas , Assistência Terminal/métodos , Preferência do Paciente , Vida IndependenteRESUMO
Advance care planning in the acute hospital: A qualitative analysis of terms and conditions Abstract: Background: Advance Care Planning (ACP) is an internationally established concept aimed to facilitate anticipatory care planning in the event of future inability to consent. In Germany, ACP is currently not regularly offered to patients in acute care hospitals. Aim: We aimed to identify preconditions for implementation of ACP in acute care hospitals in Germany through review of the international literature and expert interviews. Methods: A systematic literature search was carried out in the databases MEDLINE and CINAHL for internationally used strategies for implementing ACP in acute care hospitals. Consecutively, a guide for interviews with experts to evaluate the strategies was developed. Interviews were analyzed by qualitative content analysis according to Mayring. Results: Out of 13 included publications, 17 preconditions were identified and assigned to 16 categories after evaluation by experts. In international ACP programs, it was described how to proceed and organize the ACP conversation. German experts emphasized that appropriate preconditions, such as sufficient time resources and training, must be granted, whereas the literature search revealed the conversation process and organization as important determinants. Conclusions: The implementation of ACP programs is conceivable, but requires specific conditions as legal regulation and defining and structuring of the processes.
RESUMO
BACKGROUND: Most randomised controlled trials on advance care planning were conducted in people with advanced, life-limiting illnesses or in institutional settings. There are few studies on its effect in older people living in the community. AIM: To determine the effects of advance care planning in older community dwelling people. DESIGN: The STADPLAN study was a cluster-randomised trial with 12 months follow-up. The complex intervention comprised a 2-days training for nurse facilitators that delivered a formal advance care planning counselling and a written information brochure. Patients in the control group received optimised usual care, that is, provision of a short information brochure. SETTING/PARTICIPANTS: Home care services in three regions of Germany were randomised using concealed allocation. Care dependent clients of participating home care services, aged 60 years or older, and rated to have a life-expectancy of at least 4 weeks were included. Primary outcome was active participation in care at 12 months, assessed by blinded investigators using the Patient Activation Measure (PAM-13). RESULTS: Twenty-seven home care services and 380 patients took part. Three hundred seventy-three patients were included in the primary analysis (n = 206 in the intervention and n = 167 in the control group). There was no statistically significant difference between the intervention and control group with regard to the PAM-13 after 12 months (75.7 vs 78.4; p = 0.13). No differences in quality of life, anxiety and depression, advance care planning engagement, and in proportion of participants with advance directives were found between groups. CONCLUSIONS: The intervention showed no relevant effects on patient activation or quality of life in community dwelling older persons, possibly indicating the need for more tailored interventions. However, results are limited by a lack of statistical power. TRIAL REGISTRATION: German Clinical Trials Register: DRKS00016886.
Assuntos
Planejamento Antecipado de Cuidados , Serviços de Assistência Domiciliar , Idoso , Idoso de 80 Anos ou mais , Humanos , Diretivas Antecipadas , Vida Independente , Qualidade de VidaRESUMO
BACKGROUND: The STADPLAN study is a cluster-randomised controlled trial including 27 home care services in Germany. It assesses the effect of an advance care planning (ACP) intervention delivered by trained nurses to older care-dependent patients. Patients received two ACP conversations and an information brochure. Nurses were educated through a two-day programme and topic guides structuring the conversations. Objectives of the process evaluation were to determine: [1] whether the intervention was implemented as planned, [2] which change mechanisms were observed, [3] whether targeted process outcomes were achieved and [4] in which way contextual factors influenced the implementation process. METHODS: The process evaluation is based on a mixed methods approach following the recommendations of the UK-MRC framework for the development and evaluation of complex interventions. Qualitative and quantitative assessments were developed and analysed guided by a logic model comprising intervention, participants, mechanisms of change and context factors. The results of the main trial will be published elsewhere. RESULTS: Educational programme and topic guides were mostly implemented as planned and resulted in motivation, knowledge, and perceived competencies to facilitate ACP conversations in nurses. Deviances in the performance of ACP conversations indicated patients' varied individual needs, but also obstacles like reluctance of patients and caregivers to participate actively and time constraints of nurse facilitators. Patients and caregivers reported increased awareness of ACP, planning and other activities indicating that targeted process outcomes could be achieved. The relevance of multifaceted contextual factors acting as barriers or facilitators for the engagement in ACP interventions on the individual, organisational and macro level was evident. CONCLUSIONS: The process evaluation elicits obstacles and achievements of the ACP intervention. The logic model organised a plethora of mixed methods data into a holistic picture of multifaceted results. Nurses as ACP facilitators in home care can fulfil a crucial initiating role based on a trusting relationship with their patients. To support older care-dependent people's ACP engagement, access should be simplified. Furthermore, education for nurse facilitators and sufficient resources for service provision are needed. Independent of monetary reimbursement, healthcare providers must respect patients' choice for or against any ACP intervention. ETHICS AND TRIAL REGISTRATION: Approved by the Ethics Committees of Martin Luther University Halle-Wittenberg (Ref.-No. 2019-045), Carl von Ossietzky University Oldenburg (Ref.-No. 2019-024), and University of Lübeck (Ref.-No. 19-080). GERMAN CLINICAL TRIALS REGISTER: DRKS00016886. Registered retrospectively 04/06/2019, first participant included 29/05/2019.
Assuntos
Planejamento Antecipado de Cuidados , Serviços de Assistência Domiciliar , Alemanha , Humanos , Motivação , Estudos RetrospectivosRESUMO
Nurses' perspectives on their potential role in advance care planning in home care: A qualitative study Abstract. Background: Advance Care Planning (ACP) in long-term care in Germany has been identified as a potential area of nurses' responsibility. In the StAdPlan study (DRKS0016886), an ACP intervention in outpatient care was implemented and evaluated: Trained nurses conducted ACP conversations with patients. A comprehensive process evaluation was part of the study. Aim: A partial result of the process evaluation was analysing the perspective of nurses on their potential role as ACP facilitators for outpatients. Methods: Semi-structured interviews with nursing professionals and nursing service managers (n = 42) were carried out prior to the implementation of the ACP intervention. A qualitative content analysis of the recorded interviews was performed. Results: Participants described the importance of ACP in outpatient care, their personal motivation and competence as well as necessary contextual conditions. Nursing professionals are motivated to offer ACP to patients to be able to care for them according to their wishes. For effective ACP conversations, nurse professionals considered in-depth knowledge of ACP, conversational skills and sufficient time resources as necessary. ACP consultations can be a suitable field of action for nurses as they have access and an established relationship of trust with patients. Conclusions: Under certain conditions, nurses' role in offering guidance on ACP in outpatient care was seen as feasible and beneficial. Prerequisites for implementation are financial resources and training for nurses for this service.
Assuntos
Planejamento Antecipado de Cuidados , Serviços de Assistência Domiciliar , Enfermeiras e Enfermeiros , Humanos , Pesquisa Qualitativa , ComunicaçãoRESUMO
Advance care planning conversations in home care: Intervention development with the Behaviour Change Wheel Abstract. Background: StAdPlan is a multicenter, cluster-randomized controlled trial aimed to develop and evaluate an advance care planning (ACP) intervention for the German home care setting. Aim: This paper reports the intervention development. Available ACP concepts were reviewed and adapted to the German home care context in terms of staffing and available time resources. Skilled nurses are assigned to raise the awareness on ACP among older care-dependent people and their informal caregivers/relatives through structured conversation and facilitating the use of existing counselling services. Methods: The Behavior Change Wheel (BCW) was applied to the development of the intervention components. Results: The complex intervention addresses care-dependent people aged 65 years and above and their informal caregivers. A two-day training session qualifies nursing professionals to offer guideline-based conversations which take place at least twice at the care-dependent person's home, if possible with the involvement of relatives. An additional information brochure is provided. Conclusions: The application of the BCW model proved to be appropriate for the analysis, description and definition of the specific functions of the intervention. The intervention is prepared for the effectiveness study.
Assuntos
Planejamento Antecipado de Cuidados , Serviços de Assistência Domiciliar , Humanos , Casas de Saúde , ComunicaçãoRESUMO
BACKGROUND: In Germany, advance care planning (ACP) was first introduced by law in 2015. However, ACP is still uncommon in Germany and only few people have advance directive forms. This study aims to evaluate an ACP program in care dependent community-dwelling persons, compared to optimised usual care. METHODS: A cluster-randomised controlled trial of 12 months duration will be conducted in 3 German study sites comparing the pretested ACP-counselling offered by trained nurses with a control group receiving optimised usual care. Using external concealed randomisation, 16 home care services each will be included in the intervention and the control group (30 participants per cluster; n = 960). Eligibility criteria for patients are: ≥60 years, somehow care dependent, adequate German language skills, assumed life-expectancy of ≥4 weeks, and cognitive ability for participation. ACP will be delivered by trained nurse facilitators of the respective home care services and communication will include proxy decision-makers. The primary endpoint will be patient activation, assessed by the Patient Activation Measure (PAM-13). Secondary endpoints include ACP-engagement, proportion of prepared advance directives, number and duration of hospitalisations, quality of life as well as depression and anxiety. Further, comprehensive economic and process evaluations will be conducted. DISCUSSION: STADPLAN is the first study in Germany that assesses an adapted ACP intervention with trained nurses in home care services and the first international study focusing on cost effectiveness of ACP in community-dwelling older persons. The results will help to improve the understanding and communicating of patients' preferences regarding medical treatment and care and thereby contribute to patients' autonomy. TRIAL REGISTRATION: German Clinical Trials Register: DRKS00016886 (Date of registration: 04.06.2019).
Assuntos
Planejamento Antecipado de Cuidados , Vida Independente , Qualidade de Vida/psicologia , Diretivas Antecipadas , Idoso , Idoso de 80 Anos ou mais , Feminino , Alemanha , Humanos , Masculino , Casas de SaúdeRESUMO
Gold nanoparticles (GNP) enhance the absorbance of photons thereby increasing emission of Auger-/photoelectrons in the nm-µm range. Yet, a major disadvantage is their diameter-dependent cellular uptake with an optimum of ~50 nm which may not offer optimal radiosensitization. A method was developed to enhance the uptake of small GNP. GNP (10nm) were linked to DNA and transferred into HeLa cells by transient transfection (GNP-DT). Treatment of cells with GNP-DT resulted in a strong perinuclear focal accumulation, whereas this was dimmer and sparser for GNP-T (lacking DNA) and close to background levels in GNP-treated cells. Only GNP-DT showed a significant radiosensitizing effect (p=0.005) on clonogenic survival using clinically relevant megavolt x-rays. Our novel method markedly increases the uptake/retention and alters the localization of small GNP in cells compared to unmodified GNP. This work finally enables studying the radiosensitizing effects of differentially sized GNP. FROM THE CLINICAL EDITOR: In an effort to increase the radiosensitization of HeLa cells, his paper discusses a transient transfection-based method to enhance gold nanoparticle intracellular delivery.
Assuntos
Ouro/administração & dosagem , Nanopartículas Metálicas/administração & dosagem , Radiossensibilizantes/administração & dosagem , Transfecção , DNA/química , DNA/genética , Ouro/química , Ouro/farmacocinética , Células HeLa , Humanos , Tamanho da Partícula , Radiossensibilizantes/química , Radiossensibilizantes/farmacocinéticaRESUMO
BACKGROUND: According to recent legislation, facilitated advance care planning (ACP) for nursing home (NH) residents is covered by German sickness funds. However, the effects of ACP on patient-relevant outcomes have not been studied in Germany yet. This study investigates whether implementing a complex regional ACP intervention improves care consistency with care preferences in NH residents. METHODS: This is a parallel-group cluster-randomized controlled trial (cRCT) with 48 NHs (≈ 3840 resident beds) between 09/2019 and 02/2023. The intervention group will receive a complex, regional ACP intervention aiming at sustainable systems redesign at all levels (individual, institutional, regional). The intervention comprises comprehensive training of ACP facilitators, implementation of reliable ACP processes, organizational development in the NH and other relevant institutions of the regional healthcare system, and education of health professionals caring for the residents. Control group NHs will deliver care as usual. Primary outcome is the hospitalization rate during the 12-months observation period. Secondary outcomes include the rate of residents whose preferences were known and honored in potentially life-threatening events, hospital days, index treatments like resuscitation and artificial ventilation, advance directives, quality of life, psychological burden on bereaved families, and costs of care. The NHs will provide anonymous, aggregated data of all their residents on the primary outcome and several secondary outcomes (data collection 1). For residents who have given informed consent, we will evaluate care consistency with care preferences and further secondary outcomes, based on chart reviews and short interviews with residents, surrogates, and carers (data collection 2). Process evaluation will aim to explain barriers and facilitators, economic evaluation the cost implications. DISCUSSION: This study has the potential for high-quality evidence on the effects of a complex regional ACP intervention on NH residents, their families and surrogates, NH staff, and health care utilization in Germany. It is the first cRCT investigating a comprehensive regional ACP intervention that aims at improving patient-relevant clinical outcomes, addressing and educating multiple institutions and health care providers, besides qualification of ACP facilitators. Thereby, it can generate evidence on the potential of ACP to effectively promote patient-centered care in the vulnerable population of frail and often chronically ill elderly. TRIAL REGISTRATION: ClinicalTrials.gov ID NCT04333303 . Registered 30 March 2020.
Assuntos
Planejamento Antecipado de Cuidados , Casas de Saúde , Idoso , Alemanha , Pessoal de Saúde , Humanos , Estudos Multicêntricos como Assunto , Qualidade de Vida , Ensaios Clínicos Controlados Aleatórios como AssuntoRESUMO
BACKGROUND: Process evaluation addresses the implementation, mechanisms of impact, and context of participants in complex interventions. The STADPLAN study assesses the effects of conversations on advance care planning (ACP) led by trained nurse facilitators. The complex intervention consists of several components that may lead to various changes in attitude and behavior regarding personal ACP activities. With the process evaluation, we aim to assess how changes were achieved in the STADPLAN intervention. METHODS: The planned process evaluation study will be conducted alongside a cluster-randomized controlled trial on ACP in home care services (HCS). Trained nurse facilitators will deliver the ACP intervention consisting of an information brochure and two ACP conversations. A logic model depicts the assumed change processes of the intervention: the educational program enables nurses to conduct ACP conversations with patients and their caregivers. Patients gain knowledge and reflect upon and engage in their own ACP. Caregivers better understand patients' wishes and feel reassured in their role as surrogates. Designation of a surrogate and communication on ACP are facilitated. We will assess the effects of the educational program with questionnaires and a focus group including all participating nurses. We will measure ACP engagement, and prevalence of advance directives in patients, and ask for their experiences with the intervention. We will conduct semi-structured interviews with caregivers about their expectations and experiences regarding ACP in general and the intervention. We will address context factors, e.g., basic characteristics of the HCS (such as ownership, number of clients, staff and qualification). Analysis will be based upon the logic model, integrating qualitative and quantitative data. DISCUSSION: The comprehensive process evaluation will provide essential information on the feasibility of implementation strategies and the clinical relevance of a nurse-led ACP intervention in home care recipients and its generalizability and transferability to other settings. TRIAL REGISTRATION: German Clinical Trials Register: DRKS00016886 . Registered retrospectively on June 4, 2019, first participant included on May 29, 2019.
Assuntos
Planejamento Antecipado de Cuidados , Serviços de Assistência Domiciliar , Vida Independente , Idoso , Idoso de 80 Anos ou mais , Humanos , Enfermeiras e Enfermeiros , Ensaios Clínicos Controlados Aleatórios como AssuntoRESUMO
PURPOSE: Radiation-induced lymphocyte apoptosis (RILA) has been suggested as a predictive assay for adverse late reactions after radiotherapy. Thus, low RILA values of T-lymphocyte subpopulations have been associated with increased risk for various endpoints at 2 to 3 years of follow-up. The purpose was to test if such associations persist for specific endpoints (subcutaneous fibrosis, telangiectasia) in breast cancer patients with at least 10 years of follow-up.Experimental Design: Two hundred and seventy-two female patients who had received breast-conserving therapy within the German ISE study were included (median follow-up: 11.6 years). Radiotherapy-induced side effects were scored according to the Late Effects in Normal Tissues-Subjective, Objective, Management, and Analytic (LENT-SOMA) classification system. RILA in the CD4+, CD8+, and natural killer (NK) subpopulations from peripheral blood was analyzed by flow cytometry. Multivariate predictive modeling was performed including relevant clinical risk factors. RESULTS: Low CD4+ RILA was associated with increased risk for both fibrosis (P = 0.011) and telangiectasia (P < 0.001). For fibrosis, the association was stronger outside the surgical area (Fibout; P = 0.004) than within (Fibin; P = 0.17). Predictive multivariate modeling including clinical risk factors yielded OR of 3.48 (95% confidence interval, 1.84-6.58) for any fibrosis and 8.60 (2.71-27.3) for telangiectasia. Addition of CD4+ RILA to the clinical variables improved discrimination (c statistics) from 0.62 to 0.68 for any fibrosis, 0.62 to 0.66 for Fibin, 0.61 to 0.69 for Fibout, and from 0.65 to 0.76 for telangiectasia. CD8+ and NK RILA were not significantly associated with radiotherapy-related late reactions. CONCLUSIONS: The results provide first evidence that low CD4+ RILA is associated with increased subcutaneous fibrosis and telangiectasia even after 10 years. This supports the potential usefulness for predicting individual clinical risk.
Assuntos
Apoptose/efeitos da radiação , Neoplasias da Mama/complicações , Linfócitos T CD4-Positivos/efeitos da radiação , Telangiectasia/etiologia , Telangiectasia/patologia , Neoplasias da Mama/radioterapia , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD4-Positivos/patologia , Linfócitos T CD8-Positivos/metabolismo , Linfócitos T CD8-Positivos/efeitos da radiação , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos da radiação , Relação Dose-Resposta à Radiação , Feminino , Fibrose , Seguimentos , Humanos , Curva ROC , Lesões por RadiaçãoRESUMO
We report on a patient suffering from symptomatic spinal attacks in the form of a paroxysmal "positive" (algetic-tonic) Brown-Séquard syndrome. A cervical cord lesion, presumably inflammatory-demyelinating in origin, was identified as the morphological correlate of these attacks. Their pathogenesis is discussed in the light of similar case reports from the literature. For the first time, this rare type of seizure is published with a video documentation. It may deserve consideration in the differential diagnosis of otherwise unexplained paroxysmal events that present in an "epileptic" manner.
Assuntos
Síndrome de Brown-Séquard/diagnóstico , Distonia/diagnóstico , Epilepsia Generalizada/diagnóstico , Adulto , Síndrome de Brown-Séquard/fisiopatologia , Vértebras Cervicais , Doenças Desmielinizantes/diagnóstico , Diagnóstico Diferencial , Distonia/fisiopatologia , Epilepsia Generalizada/fisiopatologia , Seguimentos , Humanos , Estudos Longitudinais , Imageamento por Ressonância Magnética , Masculino , Gravação de VideoteipeRESUMO
An experimental intracerebral C6 glioma model in immunosuppressed female hairless rats has been developed. The rate of tumor uptake was evaluated by magnetic resonance imaging (MRI), using specific sequences without gadolinium enhancement. Twenty-four hours before intracerebral transplantation, a control cranial MRI was carried out and rats underwent a total body irradiation (TBI). MRI was repeated seven days after transplantation in order to monitor tumor uptake. Then, twelve days after transplantation, tumors were treated with two different protocols of radiotherapy: 3 Gy during 5 days or 0.7 Gy three times a day during 5 days (ultra fractionation). A third MRI was performed 21 days after intracerebral transplantation. Eventually, all the rats were sacrificed and histological analysis of the tumors was performed. Our results show that TBI efficiently increases the rate of tumor uptake. Thereafter, tumor formation and growth as well as the efficiency of a therapy (radiotherapy in our case) can be monitored with MRI (without gadolinium enhancement). Treatment of C6 glioma tumors with ultrafractionation was a marked improvement compared to a more traditional radiotherapy treatment. We developed a model that is useful for the study of new glioma treatment. We also obtained promising preliminary results when using ultra fractionation radiotherapy.
Assuntos
Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/radioterapia , Glioblastoma/patologia , Glioblastoma/radioterapia , Animais , Divisão Celular/efeitos da radiação , Modelos Animais de Doenças , Fracionamento da Dose de Radiação , Feminino , Imageamento por Ressonância Magnética , Transplante de Neoplasias , Ratos , Irradiação Corporal TotalRESUMO
In vivo, severe hypoglycemia is frequently associated with seizures. The hippocampus is a structure prone to develop seizures and seizure-induced damage. Patients with repeated hypoglycemic episodes have frequent memory problems, suggesting impaired hippocampal function. Here we studied the effects of moderate hypoglycemia on primarily generalized flurothyl-induced seizures in vivo and, using EEG recordings, we determined involvement of the hippocampus in hypoglycemic seizures. Moderate systemic hypoglycemia had proconvulsant effects on flurothyl-induced clonic (forebrain) seizures. During hypoglycemic seizures, seizure discharges were recorded in the hippocampus. Thus, we continued the studies in combined entorhinal cortex-hippocampus slices in vitro. However, in vitro, decreases in extracellular glucose from baseline 10 mM to 2 or 1 mM did not induce any epileptiform discharges. In fact, low glucose (2 and 1 mM) attenuated preexisting low-Mg2+-induced epileptiform activity in the entorhinal cortex and hippocampal CA1 region. Osmolarity compensation in low-glucose solution using mannitol impaired slice recovery. Additionally, using paired-pulse stimuli we determined that there was no impairment of GABAA inhibition in the dentate gyrus during glucopenia. The data strongly indicate that, although forebrain susceptibility to seizures is increased during moderate in vivo hypoglycemia and the hippocampus is involved during hypoglycemic seizures, glucose depletion in vitro contributes to an arrest of epileptiform activity in the system of the entorhinal cortex-hippocampus network and there is no impairment of net GABAA inhibition during glucopenia.
Assuntos
Epilepsia Generalizada/fisiopatologia , Hipoglicemia/fisiopatologia , Convulsões/fisiopatologia , Animais , Córtex Entorrinal/citologia , Córtex Entorrinal/efeitos dos fármacos , Córtex Entorrinal/metabolismo , Glucose/farmacologia , Transportador de Glucose Tipo 4/metabolismo , Hipocampo/fisiopatologia , Hipoglicemiantes/farmacologia , Técnicas In Vitro , Insulina/farmacologia , Magnésio/fisiologia , Masculino , Prosencéfalo/fisiopatologia , Ratos , Ratos Sprague-Dawley , Receptores de GABA-A/efeitos dos fármacos , Receptores de GABA-A/fisiologiaRESUMO
PURPOSE: The imbalance between neuronal inhibition and excitation contributes to epileptogenesis. Inhibition in the central nervous system (CNS) is mediated by gamma-aminobutyric acid (GABA) and glycine. Recent studies indicate the expression of glycine receptor (GlyR) in hippocampus and neocortex. However, the function of GlyR in these regions is not clarified completely. The aim of this study was to investigate whether the GlyR agonists glycine and taurine promote an anticonvulsive effect. METHODS: We induced epileptiform discharges by reducing extracellular Mg2+ concentration in combined rat entorhinal cortex-hippocampal slices (400 micro m). Epileptiform discharges were detected by using extracellular recording techniques. RESULTS: Seizure-like events were suppressed by taurine, exhibiting a half-maximal inhibitory effect (IC50) of 0.9 mM. Suppression of late recurrent discharges in the medial entorhinal cortex and recurrent short discharges in the hippocampus was obtained at an IC50 value of 1.6 and 2.1 mM, respectively. Strychnine at concentrations <1 micro M abolished these effects. Likewise glycine, after an initial proconvulsant effect, suppressed epileptiform discharges. CONCLUSIONS: These findings show that GlyR agonists, in particular taurine, could serve as potential anticonvulsants and suggest an important role of GlyR in cortical function and dysfunction.