Protocol for the development of guidance for collaborator and partner engagement in health care evidence syntheses.

BACKGROUND: Involving collaborators and partners in research may increase relevance and uptake, while reducing health and social inequities. Collaborators and partners include people and groups interested in health research: health care providers, patients and caregivers, payers of health research, payers of health services, publishers, policymakers, researchers, product makers, program managers, and the public. Evidence syntheses inform decisions about health care services, treatments, and practice, which ultimately affect health outcomes. Our objectives are to: A. Identify, map, and synthesize qualitative and quantitative findings related to engagement in evidence syntheses B. Explore how engagement in evidence synthesis promotes health equity C. Develop equity-oriented guidance on methods for conducting, evaluating, and reporting engagement in evidence syntheses METHODS: Our diverse, international team will develop guidance for engagement with collaborators and partners throughout multiple sequential steps using an integrated knowledge translation approach: 1. Reviews. We will co-produce 1 scoping review, 3 systematic reviews and 1 evidence map focusing on (a) methods, (b) barriers and facilitators, (c) conflict of interest considerations, (d) impacts, and (e) equity considerations of engagement in evidence synthesis. 2. Methods study, interviews, and survey. We will contextualise the findings of step 1 by assessing a sample of evidence syntheses reporting on engagement with collaborators and partners and through conducting interviews with collaborators and partners who have been involved in producing evidence syntheses. We will use these findings to develop draft guidance checklists and will assess agreement with each item through an international survey. 3. CONSENSUS: The guidance checklists will be co-produced and finalised at a consensus meeting with collaborators and partners. 4. DISSEMINATION: We will develop a dissemination plan with our collaborators and partners and work collaboratively to improve adoption of our guidance by key organizations. CONCLUSION: Our international team will develop guidance for collaborator and partner engagement in health care evidence syntheses. Incorporating partnership values and expectations may result in better uptake, potentially reducing health inequities.

Key issues for stakeholder engagement in the development of health and healthcare guidelines.

Established in 2015, the Multi-Stakeholder Engagement (MuSE) Consortium is an international network of over 120 individuals interested in stakeholder engagement in research and guidelines. The MuSE group is developing guidance for stakeholder engagement in the development of health and healthcare guideline development. The development of this guidance has included multiple meetings with stakeholders, including patients, payers/purchasers of health services, peer review editors, policymakers, program managers, providers, principal investigators, product makers, the public, and purchasers of health services and has identified a number of key issues. These include: (1) Definitions, roles, and settings (2) Stakeholder identification and selection (3) Levels of engagement, (4) Evaluation of engagement, (5) Documentation and transparency, and (6) Conflict of interest management. In this paper, we discuss these issues and our plan to develop guidance to facilitate stakeholder engagement in all stages of the development of health and healthcare guideline development.

A group of international researchers, patient partners, and other stakeholders are working together to create a checklist for when and how to involve stakeholders in health guideline development. Health guidelines include clinical practice guidelines, which your healthcare provider uses to determine treatments for health conditions. While working on this checklist, the team identified key issues to work on, including: (1) Definitions, roles, and settings (2) Stakeholder identification and selection (3) Levels of engagement, (4) Evaluation of engagement, (5) Documentation and transparency, and (6) Conflict of interest management. This paper describes each issue and how the team plans to produce guidance papers to address them.

Research priority setting related to older adults: a scoping review to inform the Cochrane-Campbell Global Ageing Partnership work programme.

OBJECTIVE: To explore and map the findings of prior research priority-setting initiatives related to improving the health and well-being of older adults. DESIGN: Scoping review. DATA SOURCES: Searched MEDLINE, EMBASE, AgeLine, CINAHL and PsycINFO databases from January 2014 to 26 April 2021, and the James Lind Alliance top 10 priorities. ELIGIBILITY CRITERIA: We included primary studies reporting research priorities gathered from stakeholders that focused on ageing or the health of older adults (≥60 years). There were no restrictions by setting, but language was limited to English and French. DATA EXTRACTION AND SYNTHESIS: We used a modified Reporting Guideline for Priority Setting of Health Research (REPRISE) guideline to assess the transparency of the reported methods. Population-intervention-control-outcome (PICO) priorities were categorised according to their associated International Classification of Health Interventions (ICHI) and International Classification of Functioning (ICF) outcomes. Broad research topics were categorised thematically. RESULTS: Sixty-four studies met our inclusion criteria. The studies gathered opinions from various stakeholder groups, including clinicians (n=56 studies) and older adults (n=35), and caregivers (n=24), with 75% of the initiatives involving multiple groups. None of the included priority-setting initiatives reported gathering opinions from stakeholders located in low-income or middle-income countries. Of the priorities extracted, 272 were identified as broad research topics, while 217 were identified as PICO priorities. PICO priorities that involved clinical outcomes (n=165 priorities) and interventions concerning health-related behaviours (n=59) were identified most often. Broad research topics on health services and systems were identified most often (n=60). Across all these included studies, the reporting of six REPRISE elements was deemed to be critically low. CONCLUSION: Future priority setting initiatives should focus on documenting a more detailed methodology with all initiatives eliciting opinions from caregivers and older adults to ensure priorities reflect the opinions of all key stakeholder groups.

Virtual Reality Exposure Simulation for Student Veteran Social Anxiety and PTSD: A Case Study.

Exposure based exercises are a common element of many gold standard treatments for anxiety disorders and post-traumatic stress disorder and virtual reality simulations have been evaluated as a platform for providing clients with opportunities for repeated exposure during treatment. Although research on virtual reality exposure therapy (VRET) indicates effectiveness and high levels of user satisfaction, VRETs require a participant to complete exposure exercises in-offices with specialized equipment. The current exploratory case method study evaluates the experience and outcomes of one student veteran with social anxiety disorder and PTSD completing twelve sessions of VRET exposure using a mobile phone simulation of a virtual grocery store. The participant reported decreases in psychological symptoms, improvements in neurological connectivity, and better sleep quality upon completing the trial. Results suggest that VRET using a mobile application is feasible and warrants further research to evaluate effectiveness more fully. Implications include the use of a mobile based virtual reality simulation for intervening in social anxiety for student veterans.

Protocol for the development of guidance for stakeholder engagement in health and healthcare guideline development and implementation.

BACKGROUND: Stakeholder engagement has become widely accepted as a necessary component of guideline development and implementation. While frameworks for developing guidelines express the need for those potentially affected by guideline recommendations to be involved in their development, there is a lack of consensus on how this should be done in practice. Further, there is a lack of guidance on how to equitably and meaningfully engage multiple stakeholders. We aim to develop guidance for the meaningful and equitable engagement of multiple stakeholders in guideline development and implementation. METHODS: This will be a multi-stage project. The first stage is to conduct a series of four systematic reviews. These will (1) describe existing guidance and methods for stakeholder engagement in guideline development and implementation, (2) characterize barriers and facilitators to stakeholder engagement in guideline development and implementation, (3) explore the impact of stakeholder engagement on guideline development and implementation, and (4) identify issues related to conflicts of interest when engaging multiple stakeholders in guideline development and implementation. DISCUSSION: We will collaborate with our multiple and diverse stakeholders to develop guidance for multi-stakeholder engagement in guideline development and implementation. We will use the results of the systematic reviews to develop a candidate list of draft guidance recommendations and will seek broad feedback on the draft guidance via an online survey of guideline developers and external stakeholders. An invited group of representatives from all stakeholder groups will discuss the results of the survey at a consensus meeting which will inform the development of the final guidance papers. Our overall goal is to improve the development of guidelines through meaningful and equitable multi-stakeholder engagement, and subsequently to improve health outcomes and reduce inequities in health.

Top research priorities in liver and gallbladder disorders in the UK.

OBJECTIVES: There is a mismatch between research questions considered important by patients, carers and healthcare professionals and the research performed in many fields of medicine. The non-alcohol-related liver and gallbladder disorders priority setting partnership was established to identify the top research priorities in the prevention, diagnostic and treatment of gallbladder disorders and liver disorders not covered by the James-Lind Alliance (JLA) alcohol-related liver disease priority setting partnership. DESIGN: The methods broadly followed the principles of the JLA guidebook. The one major deviation from the JLA methodology was the final step of identifying priorities: instead of prioritisation by group discussions at a consensus workshop involving stakeholders, the prioritisation was achieved by a modified Delphi consensus process. RESULTS: A total of 428 unique valid diagnostic or treatment research questions were identified. A literature review established that none of these questions were considered 'answered' that is, high-quality systematic reviews suggest that further research is not required on the topic. The Delphi panel achieved consensus (at least 80% Delphi panel members agreed) that a research question was a top research priority for six questions. Four additional research questions with highest proportion of Delphi panel members ranking the question as highly important were added to constitute the top 10 research priorities. CONCLUSIONS: A priority setting process involving patients, carers and healthcare professionals has been used to identify the top 10priority areas for research related to liver and gallbladder disorders. Basic, translational, clinical and public health research are required to address these uncertainties.

Stakeholder involvement in systematic reviews: a scoping review.

BACKGROUND: There is increasing recognition that it is good practice to involve stakeholders (meaning patients, the public, health professionals and others) in systematic reviews, but limited evidence about how best to do this. We aimed to document the evidence-base relating to stakeholder involvement in systematic reviews and to use this evidence to describe how stakeholders have been involved in systematic reviews. METHODS: We carried out a scoping review, following a published protocol. We searched multiple electronic databases (2010-2016), using a stepwise searching approach, supplemented with hand searching. Two authors independently screened and discussed the first 500 abstracts and, after clarifying selection criteria, screened a further 500. Agreement on screening decisions was 97%, so screening was done by one reviewer only. Pre-planned data extraction was completed, and the comprehensiveness of the description of methods of involvement judged. Additional data extraction was completed for papers judged to have most comprehensive descriptions. Three stakeholder representatives were co-authors for this systematic review. RESULTS: We included 291 papers in which stakeholders were involved in a systematic review. Thirty percent involved patients and/or carers. Thirty-two percent were from the USA, 26% from the UK and 10% from Canada. Ten percent (32 reviews) were judged to provide a comprehensive description of methods of involving stakeholders. Sixty-nine percent (22/32) personally invited people to be involved; 22% (7/32) advertised opportunities to the general population. Eighty-one percent (26/32) had between 1 and 20 face-to-face meetings, with 83% of these holding ≤ 4 meetings. Meetings lasted 1 h to ½ day. Nineteen percent (6/32) used a Delphi method, most often involving three electronic rounds. Details of ethical approval were reported by 10/32. Expenses were reported to be paid to people involved in 8/32 systematic reviews. DISCUSSION/CONCLUSION: We identified a relatively large number (291) of papers reporting stakeholder involvement in systematic reviews, but the quality of reporting was generally very poor. Information from a subset of papers judged to provide the best descriptions of stakeholder involvement in systematic reviews provide examples of different ways in which stakeholders have been involved in systematic reviews. These examples arguably currently provide the best available information to inform and guide decisions around the planning of stakeholder involvement within future systematic reviews. This evidence has been used to develop online learning resources. SYSTEMATIC REVIEW REGISTRATION: The protocol for this systematic review was published on 21 April 2017. Publication reference: Pollock A, Campbell P, Struthers C, Synnot A, Nunn J, Hill S, Goodare H, Watts C, Morley R: Stakeholder involvement in systematic reviews: a protocol for a systematic review of methods, outcomes and effects. Research Involvement and Engagement 2017, 3:9. https://doi.org/10.1186/s40900-017-0060-4 .

Techniques of Neutralization: A Brain Network Perspective.

Sykes and Matza introduced neutralization theory in 1957 to explain how juvenile delinquents retain a positive self-image when engaging in delinquent acts. Since then, aspects of neutralization theory have been incorporated into sociological and criminological theories to explain socially deviant behavior. Functional brain mapping research utilizing advanced magnetic resonance imaging techniques has identified complex, intrinsically organized, large-scale brain networks. Higher order operations commonly attributed to three brain networks (default mode network [DMN], central executive network [CEN], salience network [SN]) align closely with neutralization theory. This article briefly discusses brain networks in general and the DMN, CEN, and SN specifically. It also discusses how these networks are involved when engaging in the use of techniques of neutralization and offers implications for future research.

Stakeholder involvement in systematic reviews: a protocol for a systematic review of methods, outcomes and effects.

PLAIN ENGLISH SUMMARY: Researchers are expected to actively involve stakeholders (including patients, the public, health professionals, and others) in their research. Although researchers increasingly recognise that this is good practice, there is limited practical guidance about how to involve stakeholders. Systematic reviews are a research method in which international literature is brought together, using carefully designed and rigorous methods to answer a specified question about healthcare. We want to investigate how researchers have involved stakeholders in systematic reviews, and how involvement has potentially affected the quality and impact of reviews. We plan to bring this information together by searching and reviewing the literature for reports of stakeholder involvement in systematic reviews. This paper describes in detail the methods that we plan to use to do this. After carrying out comprehensive searches for literature, we will: 1. Provide an overview of identified reports, describing key information such as types of stakeholders involved, and how. 2. Pick out reports of involvement which include detailed descriptions of how researchers involved people in a systematic review and summarise the methods they used. We will consider who was involved, how people were recruited, and how the involvement was organised and managed. 3. Bring together any reports which have explored the effect, or impact, of involving stakeholders in a systematic review. We will assess the quality of these reports, and summarise their findings. Once completed, our review will be used to produce training resources aimed at helping researchers to improve ways of involving stakeholders in systematic reviews. ABSTRACT: Background There is an expectation for stakeholders (including patients, the public, health professionals, and others) to be involved in research. Researchers are increasingly recognising that it is good practice to involve stakeholders in systematic reviews. There is currently a lack of evidence about (A) how to do this and (B) the effects, or impact, of such involvement. We aim to create a map of the evidence relating to stakeholder involvement in systematic reviews, and use this evidence to address the two points above. Methods We will complete a mixed-method synthesis of the evidence, first completing a scoping review to create a broad map of evidence relating to stakeholder involvement in systematic reviews, and secondly completing two contingent syntheses. We will use a stepwise approach to searching; the initial step will include comprehensive searches of electronic databases, including CENTRAL, AMED, Embase, Medline, Cinahl and other databases, supplemented with pre-defined hand-searching and contacting authors. Two reviewers will undertake each review task (i.e., screening, data extraction) using standard systematic review processes. For the scoping review, we will include any paper, regardless of publication status or study design, which investigates, reports or discusses involvement in a systematic review. Included papers will be summarised within structured tables. Criteria for judging the focus and comprehensiveness of the description of methods of involvement will be applied, informing which papers are included within the two contingent syntheses. Synthesis A will detail the methods that have been used to involve stakeholders in systematic reviews. Papers from the scoping review that are judged to provide an adequate description of methods or approaches will be included. Details of the methods of involvement will be extracted from included papers using pre-defined headings, presented in tables and described narratively. Synthesis B will include studies that explore the effect of stakeholder involvement on the quality, relevance or impact of a systematic review, as identified from the scoping review. Study quality will be appraised, data extracted and synthesised within tables. Discussion This review should help researchers select, improve and evaluate methods of involving stakeholders in systematic reviews. Review findings will contribute to Cochrane training resources.

An Emergency Medicine Research Priority Setting Partnership to establish the top 10 research priorities in emergency medicine.

Defining research priorities in a specialty as broad as emergency medicine is a significant challenge. In order to fund and complete the most important research projects, it is imperative that we identify topics that are important to all clinicians, society and to our patients. We have undertaken a priority setting partnership to establish the most important questions facing emergency medicine. The top 10 questions reached through a consensus process are discussed.

Working together to shape the endometrial cancer research agenda: The top ten unanswered research questions.

BACKGROUND: Endometrial cancer (EC) is the most common gynaecological cancer in developed nations and its incidence is rising. As a direct consequence, more women are dying from EC despite advances in care and improved survivorship. There is a lack of research activity and funding, as well as public awareness about EC. We sought to engage patients, carers and healthcare professionals to identify the most important unanswered research questions in EC. METHODOLOGY: The priority setting methodology was developed by the James Lind Alliance and involved four key stages: gathering research questions; checking these against existing evidence; interim prioritisation; and a final consensus meeting during which the top ten unanswered research questions were agreed using modified nominal group methodology. RESULTS: Our first online survey yielded 786 individual submissions from 413 respondents, of whom 211 were EC survivors or carers, and from which 202 unique unanswered research questions were generated. 253 individuals, including 108 EC survivors and carers, completed an online interim prioritisation survey. The resulting top 30 questions were ranked in a final consensus meeting. Our top ten spanned the breadth of patient experience of this disease and included developing personalised risk scoring, refining criteria for specialist referral, understanding the underlying biology of different types of EC, developing novel personalised treatment and prevention strategies, prognostic and predictive biomarkers, increasing public awareness and interventions for psychological issues. CONCLUSION: Having established the top ten unanswered research questions in EC, we hope this galvanises researchers, healthcare professionals and the public to collaborate, coordinate and invest in research to improve the lives of women affected by EC.

A systematic scoping review of the evidence for consumer involvement in organisations undertaking systematic reviews: focus on Cochrane.

PLAIN ENGLISH SUMMARY: Cochrane is the largest international producer of systematic reviews of clinical trial evidence. We looked for published evidence that reports where consumers (patients and the public) have been involved in Cochrane systematic reviews, and also in reviews published by other organisations.We found 36 studies that reported about consumer involvement either in individual systematic reviews, or in other organisations. The studies showed that consumers were involved in reviews in a range of different ways: coordinating and producing reviews, making reviews more accessible, and spreading the results of reviews ("knowledge transfer"). The most common role was commenting on reviews ("peer reviewing"). Consumers also had other general roles, for example in educating people about evidence or helping other consumers. There were some interesting examples of new ways of involving consumers. The studies showed that most consumers came from rich and English speaking countries. There was little evidence about how consumer involvement had changed the reviews ("impact"). The studies found that consumer involvement needed to be properly supported.In future we believe that more research should be done to understand what kind of consumer involvement has the best impact; that more review authors should report how consumers have been involved; and that consumers who help with reviews should come from more varied backgrounds. ABSTRACT: Background Cochrane is the largest international producer of systematic reviews, and is committed to consumer involvement in the production and dissemination of its reviews. The review aims to systematically scope the evidence base for consumer involvement in organisations which commission, undertake or support systematic reviews; with an emphasis on Cochrane. Methods In June 2015 we searched six databases and other sources for studies of consumer involvement in organisations which commission, undertake or support systematic reviews, or in individual systematic review processes. All types of reports and evaluations were eligible. Included studies were combined in a narrative synthesis structured by the level of evaluation and the type of involvement. Results We identified 36 relevant studies. Eleven of these were evaluations at the level of a whole organisation; seven of these studied consumer involvement in Cochrane. Ten studies examined individual Cochrane review groups. Twelve studies reported on individual reviews; only two of these were Cochrane reviews. Finally, three studies were themselves syntheses of other studies. The included studies reported varying levels of consumer involvement across a wide range of activities related to review design and conduct. These included activities such as priority setting and outcome definition as well as review-specific roles such as acting as peer referees and producing plain language summaries. The level of satisfaction and awareness of impact was generally higher in studies focused on individual Cochrane review groups than in the organisation-wide studies. Conclusions There was evidence of highly variable levels and types of consumer involvement within and beyond Cochrane, but limited evidence for what makes the most effective methods and levels of involving consumers in review production. Where evidence of impact was found at the level of individual reviews and review groups it underlined the need for properly resourced and supported processes in order to derive the greatest benefit from the lived experiences of consumers who are willing to be involved. Where reviews do involve consumers, their contribution to the final result could be more clearly identified. More rigorous evaluations are needed to determine the best approach to achieving this. Trial registration Not applicable.

Exploring the challenge of health research priority setting in partnership: reflections on the methodology used by the James Lind Alliance Pressure Ulcer Priority Setting Partnership.

PLAIN ENGLISH SUMMARY: The James Lind Alliance (JLA) brings patients, carers and clinicians together in Priority Setting Partnerships (PSPs) to identify and prioritise shared uncertainties about the effects of treatment. The JLA emerged from the evidence-informed healthcare movement to address a concern that the research being carried out on treatment effectiveness is not that of most importance to patients and health professionals. In the JLA PSPs, 'hard' evidence-informed ideals meet 'soft' participatory practices. This article explores the challenges of putting co-production methods into practice by reflecting on the methods used by the JLA Pressure Ulcer PSP (JLAPUP). The JLA principles are transparency, inclusivity and avoiding waste in research. This means paying the same close critical attention to how PSPs are designed and run, as is desired in the health research which the JLA seeks to influence. JLAPUP showed that it was possible to work in partnership in a field where patients are often elderly, immobile, unrepresented and particularly unwell, many of whom are living with more than one long term condition. However, for those unfamiliar with it, 'uncertainty' was a difficult term to get to grips with. Also, it was harder for some people than others to take part and to have their voices heard and understood. In keeping with other PSPs, JLAPUP found that the nature and quality of research into pressure ulcer prevention and treatment did not reflect the priorities of those who took part. ABSTRACT: ᅟ. BACKGROUND: Studies identifying a mismatch between the priorities of academics and clinicians and those of people with direct experience of a health condition pose a challenge to the assumption that professional researchers can represent the interests of patients and the public in setting priorities for health research. The James Lind Alliance (JLA) brings patients, carers and clinicians together in Priority Setting Partnerships (PSPs) to identify and prioritise shared uncertainties about the effects of treatment. There is no formal evaluation yet to examine the different approaches used by individual PSPs and the impact these methods have on the quality of the partnership and subsequent outputs. There is no gold standard method for health research topic identification and priority setting and reporting on public involvement in this area is predominantly descriptive rather than evaluative. METHODS AND FINDINGS: The JLA Pressure Ulcer PSP (JLAPUP) was developed and worked between 2009 and 2013 to identify and prioritise the top 10 'uncertainties', or 'unanswered questions', about the effects of pressure ulcer interventions. JLAPUP identified a mismatch between the nature and quality of RCTs in pressure ulcer prevention and treatment and the kind of research evidence desired by patients or service users, carers and health professionals. Results and methods have been reported fully elsewhere. The consultative and deliberative methods used to establish health research priorities in PSPs are fundamentally interpretive. PSPs are therefore an arena in which 'hard' evidence-informed ideals meet 'soft' participatory practices. This article provides an account of the challenges faced in one particular PSP. We explain the rationale for the approaches taken, difficulties faced and the limitations at each stage, because these aspects are particularly under-reported. The JLAPUP case is used to identify possible areas for evaluation and reporting across PSPs. CONCLUSION: Engaging people with very different health and life experiences in the complexities of health science based discussions of uncertainty is challenging. This is particularly the case when engaging groups routinely excluded from participating in health research, for example, older people with multiple comorbidities. The JLA principles of transparency, inclusivity and avoiding waste in research require paying close critical attention to PSP methodology, including full evaluation and reporting of PSP processes and outcomes. Assessing the impact of PSPs is contingent on the decision making processes of commissioners and funders.

Piperazine-2,3-dicarboxylic acid derivatives as dual antagonists of NMDA and GluK1-containing kainate receptors.

Competitive N-methyl-d-aspartate receptor (NMDAR) antagonists bind to the GluN2 subunit, of which there are four types (GluN2A-D). We report that some N(1)-substituted derivatives of cis-piperazine-2,3-dicarboxylic acid display improved relative affinity for GluN2C and GluN2D versus GluN2A and GluN2B. These derivatives also display subtype selectivity among the more distantly related kainate receptor family. Compounds 18i and (-)-4 were the most potent kainate receptor antagonists, and 18i was selective for GluK1 versus GluK2, GluK3 and AMPA receptors. Modeling studies revealed structural features required for activity at GluK1 subunits and suggested that S674 was vital for antagonist activity. Consistent with this hypothesis, replacing the equivalent residue in GluK3 (alanine) with a serine imparts 18i antagonist activity. Antagonists with dual GluN2D and GluK1 antagonist activity may have beneficial effects in various neurological disorders. Consistent with this idea, antagonist 18i (30 mg/kg ip) showed antinociceptive effects in an animal model of mild nerve injury.

N-methyl-D-aspartate (NMDA) receptor NR2 subunit selectivity of a series of novel piperazine-2,3-dicarboxylate derivatives: preferential blockade of extrasynaptic NMDA receptors in the rat hippocampal CA3-CA1 synapse.

N-Methyl-d-aspartate (NMDA) receptor antagonists that are highly selective for specific NMDA receptor 2 (NR2) subunits have several potential therapeutic applications; however, to date, only NR2B-selective antagonists have been described. Whereas most glutamate binding site antagonists display a common pattern of NR2 selectivity, NR2A > NR2B > NR2C > NR2D (high to low affinity), (2S*,3R*)-1-(phenanthrene-2-carbonyl)piperazine-2,3-dicarboxylic acid (PPDA) has a low selectivity for NR2C- and NR2D-containing NMDA receptors. A series of PPDA derivatives were synthesized and then tested at recombinant NMDA receptors expressed in Xenopus laevis oocytes. In addition, the optical isomers of PPDA were resolved; the (-) isomer displayed a 50- to 80-fold greater potency than the (+) isomer. Replacement of the phenanthrene moiety of PPDA with naphthalene or anthracene did not improve selectivity. However, phenylazobenzoyl (UBP125) or phenylethynylbenzoyl (UBP128) substitution significantly improved selectivity for NR2B-, NR2C-, and NR2D-containing receptors over NR2A-containing NMDA receptors. Phenanthrene attachment at the 3 position [(2R*,3S*)-1-(phenanthrene-3-carbonyl)piperazine-2,3-dicarboxylic acid (UBP141); (2R*,3S*)-1-(9-bromophenanthrene-3-carbonyl)piperazine-2,3-dicarboxylic acid (UBP145); (2R*,3S*)-1-(9-chlorophenanthrene-3-carbonyl)piperazine-2,3-dicarboxylic acid (UBP160); and (2R*,3S*)-1-(9-iodophenanthrene-3-carbonyl)piperazine-2,3-dicarboxylic acid (UBP161)] displayed improved NR2D selectivity. UBP141 and its 9-brominated homolog (UBP145) both display a 7- to 10- fold selectivity for NR2D-containing receptors over NR2B- or NR2A-containing receptors. Schild analysis indicates that these two compounds are competitive glutamate binding site antagonists. Consistent with a physiological role for NR2D-containing receptors in the hippocampus, UBP141 (5 muM) displayed greater selectivity than PPDA for inhibiting the slow-decaying component of the NMDA receptor-mediated CA3-CA1 synaptic response in rat hippocampal slices. UBP125, UBP128, UBP141, and UBP145 may be useful tools for determining the function of NMDA receptor subtypes.

Synthesis and pharmacology of willardiine derivatives acting as antagonists of kainate receptors.

The natural product willardiine (8) is an AMPA receptor agonist while 5-iodowillardiine (10) is a selective kainate receptor agonist. In an attempt to produce antagonists of kainate and AMPA receptors analogues of willardiine with substituents at the N3 position of the uracil ring were synthesized. The N3-4-carboxybenzyl substituted analogue (38c) was found to be equipotent at AMPA and GLUK5-containing kainate receptors in the neonatal rat spinal cord. The N3-2-carboxybenzyl substituted analogue (38a) proved to be a potent and selective GLUK5 subunit containing kainate receptor antagonist when tested on native rat and human recombinant AMPA and kainate receptor subtypes. The GLUK5 kainate receptor antagonist activity was found to reside in the S enantiomer (44a) whereas the R enantiomer (44b) was almost inactive. 5-Iodo substitution of the uracil ring of 44a gave 45, which was found to have enhanced potency and selectivity for GLUK5.

Synthesis and pharmacology of N1-substituted piperazine-2,3-dicarboxylic acid derivatives acting as NMDA receptor antagonists.

The binding site for competitive NMDA receptor antagonists is on the NR2 subunit, of which there are four types (NR2A-D). Typical antagonists such as (R)-AP5 have a subunit selectivity of NR2A > NR2B > NR2C > NR2D. The competitive NMDA receptor antagonist (2R,3S)-(1-biphenylyl-4-carbonyl)piperazine-2,3-dicarboxylic acid (PBPD, 16b) displays an unusual selectivity with improved relative affinity for NR2C and NR2D vs NR2A and NR2B. Analogues of 16b bearing aroyl or aryl substituents attached to the N(1) position of piperazine-2,3-dicarboxylic acid have been synthesized to probe the structural requirements for NR2C/NR2D selectivity. A phenanthrenyl-2-carbonyl analogue, 16e, had >60-fold higher affinity for NR2C and NR2D and showed 3-5-fold selectivity for NR2C/NR2D vs NR2A/NR2B. The phenanthrenyl-3-carbonyl analogue (16f) was less potent but more selective, having 5- and 7-fold selectivity for NR2D vs NR2A and NR2B, respectively. Thus, antagonists bearing bulky hydrophobic residues have a different NR2 subunit selectivity than that of typical antagonists.

Identification of subunit- and antagonist-specific amino acid residues in the N-Methyl-D-aspartate receptor glutamate-binding pocket.

The resolved X-ray crystal structures of the glutamate-binding domain (S1/S2 domains) of the GluR2 and NR1 glutamate receptor subunits were used to model the homologous regions of the N-methyl-D-aspartate (NMDA) receptor's NR2 subunits. To test the predictive value of these models, all four stereoisomers of the antagonist 1-(phenanthren-2-carbonyl) piperazine-2,3-dicarboxylic acid (PPDA) were docked into the NR2B glutamate-binding site model. This analysis suggested an affinity order for the PPDA isomers of d-cis > L-cis > L-trans = D-trans and predicted that the 2-position carboxylate group of the cis-PPDA isomers, but not of the trans-PPDA isomers, may be interacting with histidine 486 in NR2B. Consistent with these predictions, cis-PPDA displays a 35-fold higher affinity for NR2B-containing NMDA receptors than trans-PPDA. In addition, mutating NR2B's H486 to phenylalanine decreased cis-PPDA affinity 8-fold but had no effect on trans-PPDA affinity. In contrast, the NR2B H486F mutation increased the affinity of the typical antagonists CGS-19755 [(2R*,4S*)-4-phosphonomethyl-2-piperidine carboxylic acid] and 4-(3-phosphonopropyl) piperidine-2-carboxylic acid. In the NR1-based NR2 models, there were only four subunit-specific amino acid residues exposed to the ligand-binding pocket (and six in the GluR2-based models). These residues are located at the edge of the binding pocket, suggesting that large antagonists may be necessary for subtype specificity. Of these residues, mutational analysis and modeling suggest that A414, R712, and G713 (NR2B numbering) may be especially useful for developing NR2C- and NR2D-selective NMDA receptor antagonists and that residues A414 and T428 may determine subunit variations in agonist affinity.