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Alzheimer’s Disease (AD) therapeutics based on the amyloid hypothesis have repeatedly failed in clinical trials. Together with numerous reports that amyloid is present in brains from aged individuals without cognitive dysfunction, this suggests that the association of amyloid with AD is collateral rather than causal. However, the preeminence of the amyloid hypothesis has resulted in the ‘systematic …thwart[ing of] alternative approaches’ to AD/dementia driven by a ‘cabal’ of amyloid acolytes who have effectively controlled the ideas funded and published, which startups received venture investment and which programs were advanced in biopharmaceutical companies where they consulted. As a result, dementia research is estimated to be 15–30 years behind where it could be with conflicting data ignored in favor of the amyloid dogma and clinical trial failures being ascribed to faulty design or inadequacies in the compound selection process including flawed animal models. Major concerns regarding the precise diagnosis of AD/dementia and conflicting views on the validated status of fluid biomarker assays have resulted in trials that included patients with unknown amyloid pathologies. With the failure of the amyloid approach, emerging data on the role(s) of vascular, mitochondrial and synaptic network dysfunction, infection, diabetes, sleep, hearing loss, the gut microbiome and neuroinflammation/ innate immune function as dementia targets are driving research in new directions bolstered by recent findings on the genetic, omics and systems biology associated with AD/dementia. In moving forward, lessons learnt from the amyloid debacle should be used to enhance the objective identification of AD/dementia therapeutics as a multifactorial disease syndrome.

Geoffrey Burnstock, the founder of the field of purinergic signaling research passed away in Melbourne, Australia on June 3rd, 2020, at the age of 91. With his death, the world of biomedical research lost one of its most passionate, creative and unconventional thought leaders. He was an inspiration to the many researchers he interacted with for more than 50 years and a frequent irritation to those in the administrative establishment. Geoff never considered himself a pharmacologist having being trained as a zoologist and becoming an autonomic neurophysiologist based on his evolving interests in systems and disease-related research. By the end of his life he had: published some 1550 papers; been cited more than 125,000 times; had an h-index of 156 and had supervised over 100 Ph.D. students. His indelible legacy, based on a holistic, data-based, multidisciplinary, unconventional “outside the box” approach to research was reflected in two of the seminal findings in late 20th century biomedical research: the purinergic neurotransmitter hypothesis and the concept of co-neurotransmission, both of which were initially received by his peers with considerable skepticism that at times verged on disdain. Nonetheless, while raising hackles and threatening the status quo, Geoff persevered and prevailed, becoming a mentor for several generations of biomedical researchers. In this review we provide a joint perspective on Geoff Burnstock’s legacy in research.

Deposits of amyloid plaques and neurofibrillary tangles of aggregated tau in the brain represent key hallmarks of the neurodegenerative disorder, Alzheimer’s Disease (AD) and form the basis of the major hypotheses of AD causality. To date, therapeutics that reduce brain amyloid in AD patients have demonstrated no effect in reversing the associated decline in cognition or function indicating that the amyloid hypothesis is either incorrect or that there is a point when the disease becomes independent of Aβ production or is refractory to any type of therapeutic intervention. The clinical failures of inhibitors of tau aggregation, neurotransmitter modulators and drugs repurposed from AD-associated disease indications tend to support this latter viewpoint. Current understanding of AD causality is thus incomplete, a situation that has been compounded by a debate on whether AD is a singularly distinct form of dementia and by the dogmatic promotion of hypotheses over actual clinical data. The latter has repeatedly led to compounds lacking efficacy in Phase II trials being advanced into Phase III where their lack of efficacy is routinely recapitulated. This Commentary, the first of two, discusses amyloid and tau as putative drug targets for AD in the context of the prevalence and economic and social impact of this insidious neurodegenerative disease.

Compounds targeted for the treatment of Alzheimer's Disease (AD) have consistently failed in clinical trials despite evidence for target engagement and pharmacodynamic activity. This questions the relevance of compounds acting at current AD drug targets - the majority of which reflect the seminal amyloid and, to a far lesser extent, tau hypotheses - and limitations in understanding AD causality as distinct from general dementia. The preeminence of amyloid and tau led to many alternative approaches to AD therapeutics being ignored or underfunded to the extent that their causal versus contributory role in AD remains unknown. These include: neuronal network dysfunction; cerebrovascular disease; chronic, local or systemic inflammation involving the innate immune system; infectious agents including herpes virus and prion proteins; neurotoxic protein accumulation associated with sleep deprivation, circadian rhythm and glymphatic/meningeal lymphatic system and blood-brain-barrier dysfunction; metabolic related diseases including diabetes, obesity hypertension and hypocholesterolemia; mitochondrial dysfunction and environmental factors. As AD has become increasingly recognized as a multifactorial syndrome, a single treatment paradigm is unlikely to work in all patients. However, the biomarkers required to diagnose patients and parse them into mechanism/disease-based sub-groups remain rudimentary and unvalidated as do non-amyloid, non-tau translational animal models. The social and economic impact of AD is also discussed in the context of new FDA regulatory draft guidance and a proposed biomarker-based Framework (re)-defining AD and its stages as part of the larger landscape of treating dementia via the 2013 G8 initiative to identify a disease-modifying therapy for dementia/AD by 2025.

David Triggle's career as an educator, researcher, essayist and ethicist in many ways has paralleled the post WWII emergence of the "biomedical research ecosystem" that originated in the concept of the "Endless Frontier". In the ensuing 70 years biomedical research has irreparably changed the nature of society with vaccines, the birth control pill and new generations of drugs and biologics to treat infections, sexually transmitted diseases, psychiatric disorders and cardiovascular diseases. These have led to a shift in the population demographic to the elderly and the chronically sick leading to major issues in the provision of effective and affordable healthcare for much of the world's population. In the present article, in addition to providing a brief biography and an appreciation of David Triggle's contributions to science, the authors expand on three topics in which he has had a major interest: improving the quality, reproducibility and relevance of basic biomedical research; declining career opportunities for graduates in an era of decreased funding-the end of the "Endless Frontier"; and the dynamic between the provision for universal healthcare and the dysfunctional, wasteful and politicized systems of the current medical-industrial complex in delivering healthcare.

Recent reports have highlighted studies in biomedical research that cannot be reproduced, tending to undermine the credibility, relevance and sustainability of the research process. To address this issue, a number of factors can be monitored to improve the overall probability of reproducibility. These include: (i) shortcomings in experimental design and execution that involve hypothesis conceptualization, statistical analysis, and data reporting; (ii) investigator bias and error; (iii) validation of reagents including cells and antibodies; and (iv) fraud. Historically, research data that have undergone peer review and are subsequently published are then subject to independent replication via the process of self-correction. This often leads to refutation of the original findings and retraction of the paper by which time considerable resources have been wasted in follow-on studies. New NIH guidelines focused on experimental conduct and manuscript submission are being widely adopted in the peer-reviewed literature. These, in their various iterations, are intended to improve the transparency and accuracy of data reporting via the use of checklists that are often accompanied by "best practice" guidelines that aid in validating the methodologies and reagents used in data generation. The present Editorial provides background and context to a newly developed checklist for submissions to Biochemical Pharmacology that is intended to be clear, logical, useful and unambiguous in assisting authors in preparing manuscripts and in facilitating the peer review process. While currently optional, development of this checklist based on user feedback will result in it being mandatory within the next 12 months.

The credibility and consequent sustainability of the biomedical research “ecosystem” is in jeopardy, in part due to an inability to reproduce data from the peer-reviewed literature. Despite obvious and relatively inexpensive solutions to improve reproducibility—ensuring that experimental reagents, specifically cancer cell lines and antibodies, are authenticated/validated before use and that best practices in statistical usage are incorporated into the design, analysis, and reporting of experiments—these are routinely ignored, a reflection of hubris and a comfort with the status quo on the part of many investigators. New guidelines for the peer review of publications and grant applications introduced in the past year, while well-intended, lack the necessary consequences, e.g., denial of funding, that would result in sustained improvements when scientific rigor is lacking and/or transparency is, at best, opaque. An additional factor contributing to irreproducibility is a reductionist mindset that prioritizes certainty in research outcomes over the ambiguity intrinsic to biological systems that is often reflected in “unknown unknowns”. This has resulted in a tendency towards codifying “rules” that can provide “yes-no” outcomes that represent a poor substitute for the intellectual challenge and skepticism that leads to an awareness and consideration of “unknown unknowns”. When acknowledged as potential causes of unexpected experimental outcomes, these can often transition into the “knowns” that facilitate positive, disruptive innovation in biomedical research like the human microbiome. Changes in investigator mindset, both in terms of validating reagents and embracing ambiguity, are necessary to aid in reducing issues with reproducibility.

Efforts to address reproducibility concerns in biomedical research include: initiatives to improve journal publication standards and peer review; increased attention to publishing methodological details that enable experiments to be reconstructed; guidelines on standards for study design, implementation, analysis and execution; meta-analyses of multiple studies within a field to synthesize a common conclusion and; the formation of consortia to adopt uniform protocols and internally reproduce data. Another approach to addressing reproducibility are Reproducibility Initiatives (RIs), well-intended, high-profile, systematically peer-vetted initiatives that are intended to replace the traditional process of scientific self-correction. Outcomes from the RIs reported to date have questioned the usefulness of this approach, particularly when the RI outcome differs from other independent self-correction studies that have reproduced the original finding. As a failed RI attempt is a single outcome distinct from the original study, it cannot provide any definitive conclusions necessitating additional studies that the RI approach has neither the ability nor intent of conducting making it a questionable replacement for self-correction. A failed RI attempt also has the potential to damage the reputation of the author of the original finding. Reproduction is frequently confused with replication, an issue that is more than semantic with the former denoting “similarity” and the latter an “exact copy” – an impossible outcome in research because of known and unknown technical, environmental and motivational differences between the original and reproduction studies. To date, the RI framework has negatively impacted efforts to improve reproducibility, confounding attempts to determine whether a research finding is real.

A pharmacological experiment is typically conducted to: i) test or expand a hypothesis regarding the potential role of a target in the mechanism(s) underlying a disease state using an existing drug or tool compound in normal and/or diseased tissue or animals; or ii) characterize and optimize a new chemical entity (NCE) targeted to modulate a specific disease-associated target to restore homeostasis as a potential drug candidate. Hypothesis testing necessitates an intellectually rigorous, null hypothesis approach that is distinct from a high throughput fishing expedition in search of a hypothesis. In conducting an experiment, the protocol should be transparently defined along with its powering, design, appropriate statistical analysis and consideration of the anticipated outcome (s) before it is initiated. Compound-target interactions often involve the direct study of phenotype(s) unique to the target at the cell, tissue or animal/human level. However, in vivo studies are often compromised by a lack of sufficient information on the compound pharmacokinetics necessary to ensure target engagement and also by the context-free analysis of ubiquitous cellular signaling pathways downstream from the target. The use of single tool compounds/drugs at one concentration in engineered cell lines frequently results in reductionistic data that have no physiologically relevance. This overview, focused on trends in the peer-reviewed literature, discusses the execution and reporting of experiments and the criteria recommended for the physiologically-relevant assessment of target engagement to identify viable new drug targets and facilitate the advancement of translational studies.

The receptor concept, now more than century old, remains the core concept in understanding the mechanisms of disease causality and drug action. Originally formulated in the early 1900s, receptor theory has evolved in both detail and complexity as the tools of molecular biology and increasingly sophisticated research technologies have facilitated the study of drug/ligand receptor interactions at the molecular level. The result has been a more detailed and nuanced understanding of the parameters of drug action that together with knowledge of the pleotropic nature of cellular targets and associated signaling pathways has reshaped the receptor concept. Added to the basic agonist/antagonist view of drug/ligand function, concepts like allosterism, inverse agonism, biased signaling and compound residence time have provided a broader understanding of compound-target interactions to better inform drug discovery efforts. The iteration of descriptive data from pharmacological experiments to provide generic indices of affinity and efficacy can now be used to predict expected drug/compound effects in other cell/organ systems where the sensitivity of the latter to drug effects (either via expression levels of cell surface receptors or variances in the efficiency with which those receptors are coupled to cytosolic metabolic processes) can be accommodated.

Animal models of disease represent the pinnacle of hierarchical research efforts to validate targets and compounds for therapeutic intervention. Yet models of asthma, particularly in the mouse, which, for practical reasons, has become the sine qua non of asthma research, have been a bone of contention for decades. With barely a nod to their limitations and an extensive history of translational failures, they continue to be used for target identification and to justify the clinical evaluation of new compounds. Recent improvements - including sensitization directly to the airways; use of more relevant allergens; development of a chronic rather than short-term condition; utilization of techniques to measure lung function beyond uninterpretable measures of airway hyperresponsiveness - are laudable but cannot bridge the chasm between the models and the myriad complexities of the human disorder and multiple asthma endophenotypes. While further model developments are necessary, including recognition of key environmental factors beyond allergens, the judicious integration with newer ex vivo and in vitro techniques, including human precision-cut lung slices, reprograming of patient-derived induced pluripotent stem cells and fibroblasts to epithelial and smooth muscle cells, and use of other clinical samples to create a more holistic depiction of activities, might improve their translational success.

The translational sciences represent the core element in enabling and utilizing the output from the biomedical sciences and to improving drug discovery metrics by reducing the attrition rate as compounds move from preclinical research to clinical proof of concept. Key to understanding the basis of disease causality and to developing therapeutics is an ability to accurately diagnose the disease and to identify and develop safe and effective therapeutics for its treatment. The former requires validated biomarkers and the latter, qualified targets. Progress has been hampered by semantic issues, specifically those that define the end product, and by scientific issues that include data reliability, an overt reductionistic cultural focus and a lack of hierarchically integrated data gathering and systematic analysis. A necessary framework for these activities is represented by the discipline of pharmacology, efforts and training in which require recognition and revitalization.

The worldwide incidence of Alzheimer's disease (AD) is increasing with estimates that 115 million individuals will have AD by 2050, creating an unsustainable healthcare challenge due to a lack of effective treatment options highlighted by multiple clinical failures of agents designed to reduce the brain amyloid burden considered synonymous with the disease. The amyloid hypothesis that has been the overarching focus of AD research efforts for more than two decades has been questioned in terms of its causality but has not been unequivocally disproven despite multiple clinical failures, This is due to issues related to the quality of compounds advanced to late stage clinical trials and the lack of validated biomarkers that allow the recruitment of AD patients into trials before they are at a sufficiently advanced stage in the disease where therapeutic intervention is deemed futile. Pursuit of a linear, reductionistic amyloidocentric approach to AD research, which some have compared to a religious faith, has resulted in other, equally plausible but as yet unvalidated AD hypotheses being underfunded leading to a disastrous roadblock in the search for urgently needed AD therapeutics. Genetic evidence supporting amyloid causality in AD is reviewed in the context of the clinical failures, and progress in tau-based and alternative approaches to AD, where an evolving modus operandi in biomedical research fosters excessive optimism and a preoccupation with unproven, and often ephemeral, biomarker/genome-based approaches that override transparency, objectivity and data-driven decision making, resulting in low probability environments where data are subordinate to self propagating hypotheses.

The need to develop effective treatments for Alzheimer's disease has been confounded by repeated clinical failures where promising new chemical entities that have been extensively characterized in preclinical models of Alzheimer's disease have failed to show efficacy in the human disease state. This has been attributed to: the selection of drug targets that have yet to be shown as causal to the disease as distinct from being the result of the disease process, a lack of congruence in the animal models of Alzheimer's disease, wild-type and transgenic, to the human disease, and the enrollment of patients in proof of concept clinical trials who are at too advanced a stage of the disease to respond to any therapeutic. The development of validated biomarkers that can be used for disease diagnosis and progression is anticipated to improve patient enrollment in clinical trials, to develop new animal models and to identify new disease targets for drug discovery. The present review assesses the status of current efforts in developing CSF biomarkers for Alzheimer's disease and briefly discusses the status of CSF biomarker efforts in schizophrenia, depression, Parkinson's disease and multiple sclerosis.

The discipline of biochemical pharmacology emerged in the late 1940s as a result of an increasing emphasis on understanding drug mechanisms at the cellular level. This research approach has contributed significantly to the development of many new drug classes including antihypertensive, antifective, cholesterol lowering, anti-inflammatory, and anticancer agents, as well as antipsychotics, antidepressants and anxiolytics. Biochemical pharmacology remains a major tool in drug discovery, being employed in the search for novel therapeutics for the above and other conditions and clinical challenges, such as neurodegenerative disorders, for the treatment of pain, and for development of agents that do not induce, or can overcome, antibiotic/antiviral resistance. Together with chemical, molecular, genetic, physiological, and clinical sciences, biochemical pharmacology will in the coming decades continue to be a critical component of the drug discovery process.

Neuronal nicotinic acetylcholine receptors (nAChRs) have been a target for drug discovery efforts, primarily for CNS indications, for the past two decades. While nicotine and related natural products have been used for smoking cessation in various formulations (e.g., gum, spray, patches), it was only in 2006 with the launch of varenicline (Chantix) by Pfizer for smoking cessation that a new chemical entity (NCE) originating from a rational medicinal chemistry effort targeting neuronal AChRs was approved. The current overview outlines the chronology of drug discovery efforts in nAChRs from the cloning of the receptor family in the 1980s, to initial research efforts at SIBIA, R.J. Reynolds and Abbott, to the current industry-wide interest in nAChR agonists as novel therapeutics for pain, schizophrenia and Alzheimer's Disease. Key events in the evolution of the nAChR field were the development of high throughput electrophysiological screening tools that provided the means to enable lead optimization efforts in medicinal chemistry and the discovery by John Daly at the NIH of the frog alkaloid, epibatidine, that provided the framework for the discovery of ABT-594, an alpha4beta2 agonist that is 200 times more potent than morphine as an analgesic. Over the next decade, it is anticipated that additional NCEs including antagonists and allosteric modulators (both positive and negative), interacting with various nAChR subtypes, will be advanced to the clinic in areas of high unmet medical need, e.g., pain, neurodegeneration, to provide novel medications with improved efficacy.

Brain histaminergic neurons play a prominent role in arousal and maintenance of wakefulness (W). H(3)-receptors control the activity of histaminergic neurons through presynaptic autoinhibition. The role of H(3)-receptor antagonists/inverse agonists (H(3)R-antagonists) in the potential therapy of vigilance deficiency and sleep-wake disorders were studied by assessing their effects on the mouse cortical EEG and sleep-wake cycle in comparison to modafinil and classical psychostimulants. The H(3)R-antagonists, thioperamide and ciproxifan increased W and cortical EEG fast rhythms and, like modafinil, but unlike amphetamine and caffeine, their waking effects were not accompanied by sleep rebound. Conversely, imetit (H(3)R-agonist) enhanced slow wave sleep and dose-dependently attenuated ciproxifan-induced W, indicating that the effects of both ligands involve H(3)-receptor mechanisms. Additional studies using knockout (KO) mice confirmed the essential role of H(3)-receptors and histamine-mediated transmission in the wake properties of H(3)R-antagonists. Thus ciproxifan produced no increase in W in either histidine-decarboxylase (HDC, histamine-synthesizing enzyme) or H(1)- or H(3)-receptor KO-mice whereas its waking effects persisted in H(2)-receptor KO-mice. These data validate the hypothesis that H(3)R-antagonists, through disinhibition of H(3)-autoreceptors, enhancing synaptic histamine that in turn activates postsynaptic H(1)-receptors promoting W. Interestingly amphetamine and modafinil, despite their potent arousal effects, appear unlikely to depend on histaminergic mechanism as their effects still occurred in HDC KO-mice. The present study thus distinguishes two classes of wake-improving agents: the first acting through non-histaminergic mechanisms and the second acting via histamine and supports brain H(3)-receptors as potentially novel therapeutic targets for vigilance and sleep-wake disorders.

Understanding the mechanisms of neuronal death in concert with the identification of drugable molecular targets key to this process has held great promise for the development of novel chemical entities (NCEs) to halt neurodegenerative disease progression. Two key targets involved in the apoptotic process identified over the past decade include the mixed lineage kinase (MLK) family and glyceraldehyde phosphate dehydrogenase (GAPDH). Two NCEs, CEP-1347 and TCH346, directed against these respective targets have progressed to the clinic. For each, robust neuroprotective activity was demonstrated in multiple in vitro and in vivo models of neuronal cell death, but neither NCE proved effective Parkinson's disease (PD) patients. These recent clinical failures require a reassessment of both the relevance of apoptosis to neurodegenerative disease etiology and the available animal models used to prioritize NCEs for advancement to the clinic in this area.

Understanding the molecular basis of human disease pathophysiology is critical to accurate disease diagnosis, defining disease progression and to identifying new drugs that more specifically address target diseases. Advances in the understanding of tissue function (including draft maps of the human genome) coupled with industrial-scale, 'enabling' technologies like high throughput screening, combinatorial chemistry, proteomics, etc., have generated data on a scale never before possible. Despite this, there continues to be a dearth of new drug approvals ascribed to: (i) the challenges of working with novel, often non-validated disease targets; (ii) targeting diseases (stroke, Alzheimer's) with limited (if any) treatment and ill-defined clinical trial endpoints; (iii) enhanced regulatory hurdles for drug approval; (iv) insufficient time for the new knowledge and enabling technologies to have reached a productive level. An alternate viewpoint is that unfettered access to such technologies, where exclusion rather than integration has been the hallmark, has markedly reduced the intellectual competent of the biomedical research endeavor, with perceived technological 'quick fixes' displacing the integrative, hierarchical approach of pharmacology, that with medicinal chemistry, represents the core of the drug discovery process. After two decades of profound neglect, pharmacology has re-emerged as the key discipline in providing context to the drug discovery process, facilitating more timely, context-relevant and data-driven outcomes in the search for new drugs. Rather than viewing the future of drug discovery in terms of the 'new' biologies, systems and integrative, a rubric along the lines of iPharm, integrating both established and new technologies, is required.

Proteomics, the study of cellular protein expression, is an evolving technology platform that has the potential to identify novel proteins involved in key biological processes in the cell that may serve as potential drug targets. While proteomics has considerable theoretical promise, individual cells/tissues have the potential to generate many millions of proteins while the current analytical technologies that involve the use of time-consuming two dimensional gel electrophoresis (2DIGE) and various mass spectrometry (MS) techniques are unable to handle complex biological samples without multiple high-resolution purification steps to reduce their complexity. This can significantly limit the speed of data generation and replication and requires the use of bioinformatic algorithms to reconstitute the parent proteome, a process that does not always result in a reproducible outcome. In addition, membrane bound proteins, e.g., receptors and ion channels, that are the targets of many existing drugs, are not amenable to study due, in part, to limitations in current proteomic techniques and also to these being present in low abundance and thus disproportionally represented in proteome profiles. Subproteomes with reduced complexity have been used to generate data related to specific, hypothesis-driven questions regarding target identification, protein-interaction networks and signaling pathways. However progress to date, with the exception of diagnostic proteomics in the field of cancer, has been exceedingly slow with an inability to put such studies in the context of a larger proteome, limiting the value of the information. Additionally the pathway for target validation (which can be more accurately described at the preclinical level as target confidence building) remains unclear. It is important that the ability to measure and interrogate proteomes matches expectations, avoiding a repetition of the disappointment and subsequent skepticism that accompanied what proved to be unrealistic expectations for the rapid contribution of data based on the genome maps, to biomedical research.

In the last decade, the field of purinergic pharmacology has continued to grow as the complexity of the receptor families and the various enzymes involved in purine metabolism have been defined in molecular terms. A major theme that has emerged from these studies is the functional complexity of the interactions between P1 and P2 receptors, based upon the dynamic interrelationship between ATP and adenosine as extracellular signaling molecules. It is now clear that ATP and its degradation products (particularly ADP and adenosine) form a complex cascade for the regulation of cell-to-cell communication that can function to attenuate the consequences of tissue trauma (e.g. ischemia) that involve alterations in cellular energy charge and depletion of ATP stores. In addition to the P2 receptor family, alterations in cellular ATP stores can also affect the function of other receptors, e.g. K(ATP) channels, and mitochondrial function. The discovery of pyrimidine-preferring (UTP/UDP) P2Y receptors has also raised the possibility that the corresponding nucleoside, uracil, may function as a signaling molecule.

Pharmacology is an integrative discipline that originated from activities, now nearly 7000 years old, to identify therapeutics from natural product sources. Research in the 19th Century that focused on the Law of Mass Action (LMA) demonstrated that compound effects were dose-/concentration-dependent eventually leading to the receptor concept, now a century old, that remains the key to understanding disease causality and drug action. As pharmacology evolved in the 20th Century through successive biochemical, molecular and genomic eras, the precision in understanding receptor function at the molecular level increased and while providing important insights, led to an overtly reductionistic emphasis. This resulted in the generation of data lacking physiological context that ignored the LMA and was not integrated at the tissue/whole organism level. As reductionism became a primary focus in biomedical research, it led to the fall of pharmacology. However, concerns regarding the disconnect between basic research efforts and the approval of new drugs to treat 21st Century disease tsunamis, e.g., neurodegeneration, metabolic syndrome, etc. has led to the reemergence of pharmacology, its rise, often in the semantic guise of systems biology. Against a background of limited training in pharmacology, this has resulted in issues in experimental replication with a bioinformatics emphasis that often has a limited relationship to reality. The integration of newer technologies within a pharmacological context where research is driven by testable hypotheses rather than technology, together with renewed efforts in teaching pharmacology, is anticipated to improve the focus and relevance of biomedical research and lead to novel therapeutics that will contain health care costs.

Antipsychotics, the drugs used currently for the treatment of schizophrenia, produce their therapeutic effects via the blockade of dopamine receptors. These compounds are, however, limited in their therapeutic efficacy and have side effect liabilities that also limit their use. Agents that produce antipsychotic effects by enhancing NMDA receptor function represent a viable alternative to dopamine antagonists. d -Serine, is the prototype of this approach acting as a positive allosteric modulator of the NMDA receptor to enhance antipsychotic efficacy in the clinic. A newer approach to modulating NMDA receptor function, identified by gene association studies, is pLG72/DAOA ( d -amino acid oxidase activator) a peptide that modulates d -amino acid oxidase (DAAO) activity, increasing endogenous levels of d -serine. While the initial association of DAOA with schizophrenia and its functional effects on DAAO activity have not been replicated, its identification has led to the development of several DAAO inhibitors, e.g., AS057278, CBIO and Compound 8, that are active in animal models of antipsychotic action. The complications in validating the G72 association with schizoprenia highlight the inherent challenges in translating gene-based, disease-related associations to drug discovery targets.

A recent conference entitled Purines in Cell Signalling: Targets for New Drugs, held in Rockville, Maryland, in September, 1989, was one indication of the increasing interest in developing agonists and antagonists of P1-(adenosine) and P2-(ATP) purinoceptors [1] as potential therapeutic agents. Extracellular adenosine, acting at its membrane bound A1 and A2 receptors, is a ubiquitous modulator of cellular activity. The purine can arise from several sources including ATP hydrolysis by ectokinase activity in the region of the nerve terminal [2] and from S-adenosylhomocysteine [3] and ATP within the cell. Together with its more stable analogs, adenosine is a potent inhibitor of neurotransmitter release in both the central and peripheral nervous systems, and in cardiac, adipose and other tissues. Adenosine can also affect blood pressure and heart rate as well as modulate the function of the immune, inflammatory, gastrointestinal, renal and pulmonary systems, either via its effects on transmitter release or directly via receptor mechanisms altering intracellular transduction processes.

Histamine H3 receptors regulate the release of a variety of central neurotransmitters involved in cognitive processes. A-349821 ((4′-(3-((R,R)2,5-dimethyl-pyrrolidin-1-yl)-propoxy)-biphenyl-4-yl)-morpholin-4-yl-methanone) is a novel, non-imidazole H3 receptor ligand, displaying high affinity for recombinant rat and human H3 receptors, with pKi values of 9.4 and 8.8, respectively, and high selectivity for the H3 receptor versus H1, H2, and H4 histamine receptors. A-349821 is a potent H3 receptor antagonist in a variety of models using recombinant human and rat receptors, reversing agonist induced changes in cyclic AMP formation (pKb = 8.2 and pKb = 8.1, respectively), [ 35 S ]-GTPγS binding (pKb = 9.3 and pKb = 8.6, respectively) and calcium levels (human pKb = 8.3). In native systems, A-349821 competitively reversed agonist induced inhibition of electric field stimulated guinea-pig ileum (pA2 = 9.5) and histamine-mediated inhibition of [ 3 H ]-histamine release from rat brain cortical synaptosomes (pKb = 9.2). Additionally, A-349821 inhibited constitutive GTPγS binding at both rat and human H3 receptors with respective pEC50 values of 9.1 and 8.6, demonstrating potent inverse agonist properties. In behavioral studies, A-349821 (0.4 mg/kg—4 mg/kg) potently blocked (R)-α-methylhistamine-induced dipsogenia in mice. The compound also enhanced cognitive activity in a five-trial inhibitory avoidance model in spontaneously hypertensive rat (SHR) pups at doses of 1–10 mg/kg, with the 1 mg/kg dose showing comparable efficacy to a fully efficacious dose of ciproxifan (3 mg/kg). These doses of A-349821 were without effect on spontaneous locomotor activity. Thus, A-349821 is a novel, selective non-imidazole H3 antagonist/inverse agonist with balanced high potency across species and favorable cognition enhancing effects in rats.

The effects of various piperazine-containing compounds on the release of endogenous serotonin (5-HT) from rat hypothalamic slices were evaluated. Incubation of hypothalamic slices with m-chlorophenylpiperazine ( mCPP ) or m- trifluoromethylphenylpiperazine ( mTFMPP ) evoked a potent, dose-dependent release of endogenous 5-HT that was similar in magnitude to that seen with tryptamine, p-chloroamphetamine, or fenfluramine. In the presence of the 5-HT uptake blockers fluoxetine or chlorimipramine, this release was reduced dramatically. Furthermore, removal of calcium from the incubation medium had little effect on the drug-induced release, suggesting that the release mechanism involved displacement of 5-HT stores and not depolarization-induced exocytosis. Trazodone, MK-212, and quipazine had only small effects on release. These studies show that several piperazine-containing compounds can evoke a potent release of endogenous stores of hypothalamic 5-HT in vitro, actions which should be considered together with their direct agonist activity when interpreting the CNS effects in vivo.