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Shame is one of the leading barriers to successful recovery in substance use treatment settings. This secondary analysis study examined measurement invariance of the Internalized Shame Scale (ISS) and explored changes in shame during treatment. Participants (N=105) in the parent study were recruited from a nonprofit residential treatment center for justice-involved women and were randomized to receive mindfulness-based relapse prevention or relapse prevention treatment. A series of confirmatory factor analyses were used to assess measurement invariance in a one-factor measurement model of the ISS. Latent growth curve modeling was used to examine change in shame over time. Our findings support the assumption of measurement invariance across multiple time points and across treatment conditions, supporting comparisons of stigma scores across groups and over time. Although we observed significant reductions in shame from pre- to post-treatment, there were no differences across treatment conditions. Additional research is needed to determine how distinct treatment components relate to reductions in shame among individuals receiving treatment for a substance use disorder.
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Chronic pain and opioid use disorder (OUD) are public health crises and their co-occurrence has led to further complications and public health impacts. Provision of treatments for comorbid chronic pain and OUD is paramount to address these public health crises. Medications for OUD (MOUD) are gold standard treatments for OUD that have also demonstrated benefit in pain management. However, clinics that provide MOUD for chronic pain or OUD often lack behavioral treatments to address the challenges experienced by individuals with both conditions. Developing and implementing a behavioral treatment that complements MOUD may better equip clinics to provide comprehensive care to the growing proportion of clients who present with comorbid chronic pain and OUD. In the Healing Opioid misuse and Pain through Engagement (HOPE) Trial, we are using an effectiveness-implementation hybrid design to examine the benefits of an integrated behavioral treatment and to determine the feasibility of implementing the integrated treatment into clinics that provide MOUD. The treatment integrated 2 evidence-based treatments-Acceptance and Commitment Therapy and Mindfulness-Based Relapse Prevention-to target the emotional, behavioral, and physiological sequelae of OUD and chronic pain. Implementation feasibility will include assessing changes in implementation readiness and identifying facilitators and barriers to implementing the integrated treatment among all personnel employed in clinics that provide MOUD. This commentary offers an overview of the study and design and details adaptations we made to our study protocol, based largely on clinic personnel time constraints and variable clinic procedures during the COVID-19 pandemic.
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Animals are used for scientific purposes across Africa to benefit humans, animals or the environment. Nonetheless, ethical and regulatory oversight remains limited in many parts of the continent. To strengthen this governance framework, the Pan-African Network for Laboratory Animal Science and Ethics brought together experts from 12 African countries to create an Africa-centric practical guide to facilitate the establishment and appropriate functioning of Institutional Animal Ethics Committees across Africa. The Guidelines are based on universal principles for the care and use of sentient animals for scientific purposes, with consideration of the cultural, religious, political and socio-economic diversity in Africa. They focus on 11 key elements, including responsibilities of institutions and of the Institutional Official; composition of the Committee; its responsibilities, functioning and authority; ethical application and review processes; oversight and monitoring of animal care and use and of training and competence; quality assurance; and the roles of other responsible parties. The intent is for African institutions to adopt and adapt the guidelines, aligning with existing national legislation and standards where relevant, thus ensuring incorporation into practice. More broadly, the Guidelines form an essential component of the growing discourse in Africa regarding moral considerations of, and appropriate standards for, the care and use of animals for scientific purposes. The increased establishment of appropriately functioning animal ethics committees and robust ethical review procedures across Africa will enhance research quality and culture, strengthen societal awareness of animals as sentient beings, improve animal well-being, bolster standards of animal care and use, and contribute to sustainable socio-economic development.
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Comités de Atención Animal , Ciencia de los Animales de Laboratorio , Animales , Humanos , ÁfricaRESUMEN
Cognitive behavioral therapy (CBT) is a commonly used treatment for substance use disorders (SUDs) but has not been evaluated using the American Psychological Association's "Tolin Criteria" for determining the empirical basis of psychological treatments. The current systematic review evaluated five meta-analyses of CBT for SUD. One meta-analysis had sufficient quality to be considered in the evaluation of effect sizes. CBT produced small to moderate effects on substance use when compared to inactive treatment and was most effective at early follow-up (1-6 months post-treatment) compared to late follow-up (8+ months post-treatment). Sensitivity analyses including all five meta-analyses found similar results. A "strong recommendation" was provided for CBT as an empirically supported treatment for SUD, based on effects on substance use, quality of evidence, and consideration of contextual factors (e.g., efficacy in diverse populations).
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Animal research ethics and animal welfare in science have become progressively tightly regulated, and ethical integrity and scientific quality, as well as social responsiveness and responsibility have become key requirements for research to be approved, funded, published, and accepted. The multitude of factors to contemplate has in some instances not only become complex, requiring a team approach, but often perceived as confusing and overwhelming. To facilitate a process of simplistic yet comprehensive conceptualization, we developed the 12 Rs Framework to act as a mind map to guide scientists, oversight structures, and other stakeholders through the myriad of ethical considerations. It unfolds into three domains of twelve encompassing ethical principles, values, and other considerations, including the animal welfare, social values, and scientific integrity domains, whilst also recognizing the diversity of local context, legal requirements, values, and cultures around the globe. In the end, it can be seen as a unifying ethical framework to foster and promote animal research ethics.
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While laboratory animal research continues to be crucial for scientific and medical advancement, it still raises relevant ethical considerations. In order to foster public trust and support, all animal use must be relevant, responsible, competent and humane, and education and training of scientists in laboratory animal science (LAS) is vital to achieve these goals. However, education must be effective in generating meaningful learning and promoting a culture of competence, professionalism, accountability and transparency. With the ongoing technological and pedagogical revolution in education, LAS educators are adopting innovative educational practices, including e-learning modules, interactive simulations and virtual reality tools, to create and deliver inspirational educational experiences that are immersive, interactive, learner-centric and effective. Drawing from their expertise and experience, the authors of the articles included in this special edition bring forward new technologies and approaches, as well as novel perspectives to well-established concepts and methodologies, hopefully valuable contributions for better engagement and improved learning on LAS and the 3Rs.
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Experimentación Animal , Ciencia de los Animales de Laboratorio , Animales , Ciencia de los Animales de Laboratorio/educación , Animales de LaboratorioRESUMEN
BACKGROUND: Chronic pain and opioid use disorder (OUD) individually represent a risk to health and well-being. Concerningly, there is evidence that they are frequently co-morbid. While few treatments exist that simultaneously target both conditions, preliminary work has supported the feasibility of an integrated behavioral treatment targeting pain interference and opioid misuse. This treatment combined Acceptance and Commitment Therapy (ACT) and Mindfulness-Based Relapse Prevention (ACT+MBRP). This paper describes the protocol for the adequately powered efficacy study of this integrated treatment. METHODS: A multisite randomized controlled trial will examine the efficacy of ACT+MBRP in comparison to a parallel education control condition, focusing on opioid safety and pain education. Participants include veterans (n = 160; 21-75 years old) recruited from three Veterans Administration (VA) Healthcare Systems with chronic pain who are on a stable dose of buprenorphine. Both conditions include twelve weekly 90 min group sessions delivered via telehealth. Primary outcomes include pain interference (Patient Reported Outcome Measurement Information System - Pain Interference) and hazardous opioid use (Current Opioid Misuse Measure), which will be examined at the end of the active treatment phase and through 12 months post-intervention. Secondary analyses will evaluate outcomes including pain intensity, depression, pain-related fear, and substance use, as well as treatment mechanisms. CONCLUSION: This study will determine the efficacy of an integrated behavioral treatment program for pain interference and hazardous opioid use among veterans with chronic pain and OUD who are prescribed buprenorphine, addressing a critical need for more integrated treatments for chronic pain and OUD. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04648228.
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Terapia de Aceptación y Compromiso , Buprenorfina , Dolor Crónico , Trastornos Relacionados con Opioides , Veteranos , Humanos , Adulto Joven , Adulto , Persona de Mediana Edad , Anciano , Analgésicos Opioides/uso terapéutico , Dolor Crónico/tratamiento farmacológico , Trastornos Relacionados con Opioides/tratamiento farmacológico , Buprenorfina/uso terapéuticoRESUMEN
Despite the recognised need for education and training in laboratory animal science (LAS) and ethics in Africa, access to such opportunities has historically been limited. To address this, the Pan-African Network for Laboratory Animal Science and Ethics (PAN-LASE) was established to pioneer a support network for the development of education and training in LAS and ethics across the African continent.In the 4.5 years since the establishment of PAN-LASE, 3635 individuals from 28 African countries have participated in our educational activities. Returning to their home institutions, they have both established and strengthened institutional and regional hubs of knowledge and competence across the continent. Additionally, PAN-LASE supported the development of guidelines for establishment of institutional Animal Ethics Committees, a critical step in the implementation of ethical review processes across the continent, and in enhancing animal welfare and scientific research standards.Key challenges and opportunities for PAN-LASE going forward include the formalisation of the network; the sustainability of education and training programmes; implementation of effective hub-and-spoke models of educational provision; strengthening governance frameworks at institutional, national and regional levels; and the availability of Africa-centric open access educational resources.Our activities are enhancing animal welfare and the quality of animal research undertaken across Africa, enabling African researchers to undertake world-leading research to offer solutions to the challenges facing the continent. The challenges, successes and the lessons learnt from PAN-LASE's journey are applicable to other low- and middle-income countries across the world seeking to enhance animal welfare, research ethics and ethical review in their own country or region.
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Experimentación Animal , Ciencia de los Animales de Laboratorio , Animales , Países en Desarrollo , Ética en Investigación , Bienestar del AnimalRESUMEN
Article 23(2) of the European Union Directive 2010/63/EU, which regulates welfare provisions for animals used for scientific purposes, requires that staff involved in the care and use of animals for scientific purposes be adequately educated and trained before they undertake any such work. However, the nature and extent of such training is not stipulated in the Directive. To facilitate Member States in fulfilling their education and training obligations, the European Commission developed a common Education and Training Framework, which was endorsed by the Member States Competent Authorities. An Education & Training Platform for Laboratory Animal Science (ETPLAS) Working Group was recently established to develop further guidance to the Learning Outcomes in the Framework, with the objective to clarify the levels of knowledge and understanding required by trainees, and to provide the criteria by which these Learning Outcomes should be assessed. Using the Framework document as a starting point, assessment criteria for the Learning Outcomes of the modules required for Function A persons (carrying out procedures on animals) for rats, mice and zebrafish were created with sufficient detail to enable trainees, providers and assessors to appreciate the level of knowledge, understanding and skills required to pass each module. Adoption and utilization of this document by training providers and accrediting or approving bodies will harmonize introductory education and training for those involved in the care and use of animals for scientific purposes within the European Union, promote mutual recognition of training within and between Member States and therefore free movement of personnel.
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Bienestar del Animal/normas , Unión Europea , Ciencia de los Animales de Laboratorio/normas , Ratones , Ratas , Pez Cebra , Bienestar del Animal/ética , Animales , Ciencia de los Animales de Laboratorio/éticaRESUMEN
Despite the development of powerful molecular biological techniques and technologies, studies involving research animals remain a key component of discovery biology, and in the discovery and development of new medicines. In 1959, The Principles of Humane Experimental Technique, the 3Rs (Replacement, Reduction and Refinement) were developed to provide a framework to ensure animal research was undertaken as humanely as possible. Sixty years since their inception, the extent to which the 3Rs have been adopted and implemented by the global scientific and medical research communities has unfortunately been slow and patchy. However, this situation is changing rapidly as awareness increases, not only of the 3Rs themselves, but of the impact of animal welfare on the reproducibility, reliability and translatability of data from animal studies.
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Experimentación Animal , Derechos del Animal/legislación & jurisprudencia , Alternativas a las Pruebas en Animales/normas , Modelos Animales , Bienestar del Animal , Animales , Animales de Laboratorio , Investigación Biomédica , Guías como Asunto , Humanos , Reproducibilidad de los Resultados , Proyectos de InvestigaciónRESUMEN
Open educational resources (OERs) are becoming increasingly common as a tool in education, particularly in medical and biomedical education. However, three key barriers have been identified to their use: 1) lack of awareness of OERs, 2) lack of motivation to use OERs, and 3) lack of training in the use of OERs. Here, we explore these three barriers with teachers of medical and biomedical science to establish how best to enhance the use of OERs to improve pedagogical outcomes. An online survey was completed by 209 educators, many of whom (68.4%) reported using OERs in their teaching and almost all (99.5%) showing awareness of at least one OER. The results suggest that key problems that prevent educators from adopting OERs in their teaching include suitability for particular classes, time, and copyright. Most (81.8%) educators were somewhat, very, or extremely comfortable with OERs so there is no innate motivational barrier to adoption. A lack of training was reported by 13.9% of respondents, and 40% of respondents stated that there was little or no support from their institutions. OER users were no more comfortable with technology or better supported by departments but tended to be aware of a greater number of sources of OERs. Our study illustrates key opportunities for the expansion of OER use in physiology and medical teaching: increased breadth of awareness, increased institutional support (including time, training, and copyright support), and greater sharing of diverse OERs to suit the range of teaching challenges faced by staff in different subdisciplines.
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Educación Médica/métodos , Tecnología Educacional/métodos , Internet , Fisiología/educación , Facultades de Medicina , Universidades , Educación Médica/tendencias , Femenino , Humanos , Internet/tendencias , Masculino , Facultades de Medicina/tendencias , Encuestas y Cuestionarios , Universidades/tendenciasRESUMEN
Improving laboratory animal science and welfare requires both new scientific research and insights from research in the humanities and social sciences. Whilst scientific research provides evidence to replace, reduce and refine procedures involving laboratory animals (the '3Rs'), work in the humanities and social sciences can help understand the social, economic and cultural processes that enhance or impede humane ways of knowing and working with laboratory animals. However, communication across these disciplinary perspectives is currently limited, and they design research programmes, generate results, engage users, and seek to influence policy in different ways. To facilitate dialogue and future research at this interface, we convened an interdisciplinary group of 45 life scientists, social scientists, humanities scholars, non-governmental organisations and policy-makers to generate a collaborative research agenda. This drew on methods employed by other agenda-setting exercises in science policy, using a collaborative and deliberative approach for the identification of research priorities. Participants were recruited from across the community, invited to submit research questions and vote on their priorities. They then met at an interactive workshop in the UK, discussed all 136 questions submitted, and collectively defined the 30 most important issues for the group. The output is a collaborative future agenda for research in the humanities and social sciences on laboratory animal science and welfare. The questions indicate a demand for new research in the humanities and social sciences to inform emerging discussions and priorities on the governance and practice of laboratory animal research, including on issues around: international harmonisation, openness and public engagement, 'cultures of care', harm-benefit analysis and the future of the 3Rs. The process outlined below underlines the value of interdisciplinary exchange for improving communication across different research cultures and identifies ways of enhancing the effectiveness of future research at the interface between the humanities, social sciences, science and science policy.
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Bienestar del Animal , Ciencia de los Animales de Laboratorio/métodos , Bienestar del Animal/ética , Animales , Conducta Cooperativa , Humanidades , Humanos , Estudios Interdisciplinarios , Ciencia de los Animales de Laboratorio/ética , Ciencias SocialesRESUMEN
The Indian Pharmaceutical Industry is undergoing rapid development and expansion. Critical to this process, and the future of drug discovery in India is the continued education and training of integrative or in vivo pharmacologists, equipped with the knowledge, skills and expertise to undertake studies using laboratory animals. Modern in vivo pharmacologists not only require manual or technical skills, but a much broader education including in animal welfare, ethics, the principles of the replacement, refinement and reduction of animals in research, and nonanimal alternative techniques. This education, training, and continued professional development throughout their careers can be provided, in part, through the use of online e-learning resources. While many excellent resources exist, they are hard to locate and not widely known to the community. To address this issue, Education and Training Resources in In vivo Sciences, a free website which provides access to free open access e-learning resources in in vivo pharmacology was developed. Use of this resource by researchers and educators will result in better-trained researchers and members of ethical review committees, which in turn will raise animal welfare standards, minimize the pain, suffering and distress of laboratory animals, and enhance scientific research.
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Farmacología/educación , Bienestar del Animal , Animales , IndiaRESUMEN
We investigated whether spinalized animals can produce inspiratory rhythm. We recorded spinal inspiratory phrenic (PNA) and cranial inspiratory hypoglossal (HNA) nerve activity in the perfused brainstem preparation of rat. Complete transverse transections were performed at 1.5 (pyramidal decussation) or 2mm (first cervical spinal segment) caudal to obex. Excitatory drive was enhanced by either extracellular potassium, hypercapnia or by stimulating arterial chemoreceptors. Caudal transections immediately eliminated descending network drive for PNA, while the cranial inspiratory HNA remained unaffected. After transection, PNA bursting remained sporadic even during enhanced excitatory drive. This implies, cervical spinal circuits lack intrinsic rhythmogenic capacity. Rostral transections also abolished PNA immediately. However, HNA also progressively lost its amplitude and rhythm. Chemoreceptor activation only triggered tonic, non-rhythmic HNA. Thus the integrity of ponto-medullary circuitry was maintained. Our results suggest that an area overlapping the caudal nucleus retroambiguus provides critical ascending input to the ponto-medullary respiratory network for inspiratory rhythm generation.
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Bulbo Raquídeo/fisiología , Mecánica Respiratoria/fisiología , Animales , Presión Sanguínea/fisiología , Células Quimiorreceptoras/fisiología , Femenino , Frecuencia Cardíaca/fisiología , Hipercapnia/fisiopatología , Nervio Hipogloso/citología , Nervio Hipogloso/fisiología , Masculino , Bulbo Raquídeo/irrigación sanguínea , Neuronas Motoras/fisiología , Red Nerviosa/irrigación sanguínea , Red Nerviosa/fisiología , Nervio Frénico/citología , Nervio Frénico/fisiología , Puente/irrigación sanguínea , Puente/fisiología , Potasio/farmacología , Ratas , Ratas Sprague-Dawley , Flujo Sanguíneo Regional/fisiología , Músculos Respiratorios/fisiología , Médula Espinal/irrigación sanguínea , Médula Espinal/fisiología , Traumatismos de la Médula Espinal/fisiopatologíaRESUMEN
Alzheimer's disease (AD) is accompanied by memory loss due to neuronal cell death caused by toxic amyloid ß-peptide (Aß) aggregates. In the healthy brain, a group of amyloid-degrading enzymes including neprilysin (NEP) maintain Aß levels at physiologically low concentrations but, with age and under some pathological conditions, expression and activity of these enzymes decline predisposing to late-onset AD. Hence, up-regulation of NEP might be a viable strategy for prevention of Aß accumulation and development of the disease. As we have recently shown, inhibitors of histone deacetylases, in particular, valproic acid (VA), were capable of up-regulating NEP expression and activity in human neuroblastoma SH-SY5Y cell lines characterised by very low levels of NEP. In the present study, analysing the effect of i.p. injections of VA to rats, we have observed up-regulation of expression and activity of NEP in rat brain structures, in particular, in the hippocampus. This effect was brain region- and age-specific. Administration of VA has also restored NEP activity and memory deficit in adult rats caused by prenatal hypoxia. This suggests that VA and more specific HDAC inhibitors can be considered as potential pharmaceutical agents for up-regulation of NEP activity and improvement of cognitive functions of ageing brain.
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Enfermedad de Alzheimer/tratamiento farmacológico , Trastornos de la Memoria/tratamiento farmacológico , Memoria/efectos de los fármacos , Neprilisina/genética , Ácido Valproico/farmacología , Enfermedad de Alzheimer/psicología , Animales , Anticonvulsivantes/farmacología , Línea Celular Tumoral , Modelos Animales de Enfermedad , Femenino , Humanos , Masculino , Memoria/fisiología , Trastornos de la Memoria/psicología , Neprilisina/metabolismo , Neuroblastoma/química , Neuroblastoma/patología , Neuroblastoma/psicología , Ratas , Ratas WistarRESUMEN
We sought to determine whether histamine has effects on single neurons in the dorsal vagal complex of the brainstem since previous studies have suggested a role for histamine receptors in this region. Using whole-cell patch clamp recordings from neurons within the nucleus of the tractus solitarius (NTS) and the dorsal vagal nucleus (DVN), histamine (20 microM) depolarized a small proportion of neurons in these regions accompanied by a decrease in input resistance. Although few neurons were depolarized (21% of NTS neurons and 15% of DVN neurons), those that were affected showed robust depolarizations of 13 mV. These depolarizations were antagonized by the histamine H1 receptor antagonist triprolidine (2 microM) and were subject to a level of desensitization. Neither histamine nor the H3 receptor agonist imetit caused any change in the amplitudes of excitatory or inhibitory postsynaptic potentials elicited in NTS neurons by stimulation of the solitary tract. These data indicate that histamine has a restricted but profound effect on neurons in the dorsal vagal complex.
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Agonistas de los Receptores Histamínicos/farmacología , Histamina/farmacología , Núcleo Solitario/efectos de los fármacos , Núcleo Solitario/fisiología , Nervio Vago/efectos de los fármacos , Nervio Vago/fisiología , Animales , Sistema Nervioso Autónomo/efectos de los fármacos , Sistema Nervioso Autónomo/fisiología , Potenciales Postsinápticos Excitadores/efectos de los fármacos , Potenciales Postsinápticos Inhibidores/efectos de los fármacos , Masculino , Técnicas de Placa-Clamp , Ratas , Ratas Wistar , Receptores Histamínicos H1/fisiologíaRESUMEN
Voltage-gated potassium (Kv) channels are essential components of neuronal excitability. The Kv3.4 channel protein is widely distributed throughout the central nervous system (CNS), where it can form heteromeric or homomeric Kv3 channels. Electrophysiological studies reported here highlight a functional role for this channel protein within neurons of the dorsal vagal nucleus (DVN). Current clamp experiments revealed that blood depressing substance (BDS) and intracellular dialysis of an anti-Kv3.4 antibody prolonged the action potential duration. In addition, a BDS sensitive, voltage-dependent, slowly inactivating outward current was observed in voltage clamp recordings from DVN neurons. Electrical stimulation of the solitary tract evoked EPSPs and IPSPs in DVN neurons and BDS increased the average amplitude and decreased the paired pulse ratio, consistent with a presynaptic site of action. This presynaptic modulation was action potential dependent as revealed by ongoing synaptic activity. Given the role of the Kv3 proteins in shaping neuronal excitability, these data highlight a role for homomeric Kv3.4 channels in spike timing and neurotransmitter release in low frequency firing neurons of the DVN.
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Bulbo Raquídeo/metabolismo , Neuronas/metabolismo , Neurotoxinas/toxicidad , Canales de Potasio con Entrada de Voltaje/metabolismo , Canales de Potasio Shaw/metabolismo , Nervio Vago/metabolismo , Potenciales de Acción/efectos de los fármacos , Potenciales de Acción/fisiología , Animales , Anticuerpos/farmacología , Estimulación Eléctrica , Potenciales Postsinápticos Excitadores/fisiología , Potenciales Postsinápticos Inhibidores/fisiología , Masculino , Bulbo Raquídeo/citología , Bulbo Raquídeo/efectos de los fármacos , Vías Nerviosas/efectos de los fármacos , Vías Nerviosas/metabolismo , Neuronas/efectos de los fármacos , Técnicas de Placa-Clamp , Canales de Potasio con Entrada de Voltaje/efectos de los fármacos , Ratas , Ratas Wistar , Canales de Potasio Shaw/efectos de los fármacos , Núcleo Solitario/citología , Núcleo Solitario/metabolismo , Transmisión Sináptica/efectos de los fármacos , Transmisión Sináptica/fisiología , Nervio Vago/citología , Nervio Vago/efectos de los fármacosRESUMEN
Microinjection of opioid receptor agonists into the nucleus tractus solitarius (NTS) has differential effects on cardiovascular, respiratory, and gastrointestinal responses. This can be achieved either by presynaptic modulation of inputs onto neurons or by postsynaptic activation of receptors on neurons in specific regions. Therefore we sought to determine whether responses of neurons to activation of opioid receptors were dependent on their location within the NTS. Using whole cell patch-clamp recordings from neurons within the NTS, the mu opioid receptor (MOR) agonist [D-Ala(2), N-Me-Phe(4),Gly(5)-ol]-enkephalin (DAMGO, 100 nM) hyperpolarized a proportion of neurons in the medial, dorsomedial and dorsolateral NTS, whereas no postsynaptic responses were observed in remaining subdivisions. DAMGO reduced the amplitude of solitary tract-evoked excitatory postsynaptic potentials (EPSPs) in all neurons tested, regardless of subdivision. The kappa opioid receptor (KOR) agonist U69593 (10-20 microM) also hyperpolarized a small fraction of neurons (6/79) and decreased the amplitude of EPSPs in 50% of neurons. In contrast, the delta-opioid receptor agonist DPDPE (1-4 microM) had no presynaptic or postsynaptic effects on NTS neurons even after preincubation with bradykinin. Anatomical data at the light and electron microscopic level complemented electrophysiological observations with respect to MOR location and further showed that MORs were present at both presynaptic and postsynaptic sites in the dorsolateral NTS, often at the same synapse. These data demonstrate site specific responses of neurons to activation of MORs and KORs, which may underlie their ability to modulate different autonomic reflexes.
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Neuronas/fisiología , Receptores Opioides mu/metabolismo , Núcleo Solitario/citología , Analgésicos Opioides/farmacología , Animales , Animales Recién Nacidos , Interacciones Farmacológicas , Estimulación Eléctrica/métodos , Potenciales Postsinápticos Excitadores/efectos de los fármacos , Potenciales Postsinápticos Excitadores/fisiología , Potenciales Postsinápticos Excitadores/efectos de la radiación , Técnicas In Vitro , Masculino , Microscopía Inmunoelectrónica/métodos , Neuronas/ultraestructura , Técnicas de Placa-Clamp/métodos , Ratas , Ratas Wistar , Receptores Opioides mu/agonistas , Receptores Opioides mu/antagonistas & inhibidores , Receptores Opioides mu/ultraestructura , Somatostatina/análogos & derivados , Somatostatina/farmacologíaRESUMEN
The voltage-gated potassium channel subunit Kv3.1 confers fast firing characteristics to neurones. Kv3.1b subunit immunoreactivity (Kv3.1b-IR) was widespread throughout the medulla oblongata, with labelled neurones in the gracile, cuneate and spinal trigeminal nuclei. In the nucleus of the solitary tract (NTS), Kv3.1b-IR neurones were predominantly located close to the tractus solitarius (TS) and could be GABAergic or glutamatergic. Ultrastructurally, Kv3.1b-IR was detected in NTS terminals, some of which were vagal afferents. Whole-cell current-clamp recordings from neurones near the TS revealed electrophysiological characteristics consistent with the presence of Kv3.1b subunits: short duration action potentials (4.2 +/- 1.4 ms) and high firing frequencies (68.9 +/- 5.3 Hz), both sensitive to application of TEA (0.5 mm) and 4-aminopyridine (4-AP; 30 mum). Intracellular dialysis of an anti-Kv3.1b antibody mimicked and occluded the effects of TEA and 4-AP in NTS and dorsal column nuclei neurones, but not in dorsal vagal nucleus or cerebellar Purkinje cells (which express other Kv3 subunits, but not Kv3.1b). Voltage-clamp recordings from outside-out patches from NTS neurones revealed an outward K(+) current with the basic characteristics of that carried by Kv3 channels. In NTS neurones, electrical stimulation of the TS evoked EPSPs and IPSPs, and TEA and 4-AP increased the average amplitude and decreased the paired pulse ratio, consistent with a presynaptic site of action. Synaptic inputs evoked by stimulation of a region lacking Kv3.1b-IR neurones were not affected, correlating the presence of Kv3.1b in the TS with the pharmacological effects.