Discovery of BI-9508, a Brain-Penetrant GPR88-Receptor-Agonist Tool Compound for Mouse Studies.

Decreased activity and expression of the G-protein coupled receptor GPR88 is linked to many behavior-linked neurological disorders. Published preclinical GPR88 allosteric agonists all have pharmacokinetic properties that preclude their progression to the clinic, including high lipophilicity and poor brain penetration. Here, we describe our attempts to improve GPR88 agonists' drug-like properties and our analysis of the trade-offs required to successfully target GPR88's allosteric pocket.

Rapid-acting antidepressant drugs modulate affective bias in rats.

How rapid-acting antidepressants (RAADs), such as ketamine, induce immediate and sustained improvements in mood in patients with major depressive disorder (MDD) is poorly understood. A core feature of MDD is the prevalence of cognitive processing biases associated with negative affective states, and the alleviation of negative affective biases may be an index of response to drug treatment. Here, we used an affective bias behavioral test in rats, based on an associative learning task, to investigate the effects of RAADs.

Investigating neuropsychological and reward-related deficits in a chronic corticosterone-induced model of depression.

Chronic stress is a known risk factor for the development of major depression (MDD) and is commonly used to induce a depression-like phenotype in rodents. Similar phenotypic effects are also observed in rodents when treated chronically with the stress hormone corticosterone. In this study, we investigated the neuropsychological consequences of chronic corticosterone treatment in male rats using two translational rodent assays of affective bias, the judgement bias task (JBT) and affective bias test (ABT).

Dopamine modulating agents alter individual subdomains of motivation-related behavior assessed by touchscreen procedures.

Development of novel treatments for motivational deficits experienced by individuals with schizophrenia and major depressive disorder requires procedures that reliably assess effort-related behavior in pre-clinical models. High-throughput touchscreen-based testing, that parallels the computerized assessment of human patients, offers a platform for the establishment of tasks with high level of translational validity. Considerable efforts have been made to validate the touchscreen version of tasks that measure the degree of effort an animal is willing to invest for a reward, such as progressive ratio task.

Symptomatic and preventive effects of the novel phosphodiesterase-9 inhibitor BI 409306 in an immune-mediated model of neurodevelopmental disorders.

BI 409306, a phosphodiesterase-9 inhibitor under development for treatment of schizophrenia and attenuated psychosis syndrome (APS), promotes synaptic plasticity and cognition. Here, we explored the effects of BI 409306 treatment in the polyriboinosinic-polyribocytidilic acid (poly[I:C])-based mouse model of maternal immune activation (MIA), which is relevant to schizophrenia and APS. In Study 1, adult offspring received BI 409306 0.

Effects of pro-depressant and immunomodulatory drugs on biases in decision-making in the rat judgement bias task.

Studies in human and non-human species suggest that decision-making behaviour can be biased by an affective state, also termed an affective bias. To study these behaviours in non-human species, judgement bias tasks (JBT) have been developed. Animals are trained to associate specific cues (tones) with a positive or negative/less positive outcome.

Role of the medial prefrontal cortex in the effects of rapid acting antidepressants on decision-making biases in rodents.

Major depressive disorder is a significant and costly cause of global disability. Until the discovery of the rapid acting antidepressant (RAAD) effects of ketamine, treatments were limited to drugs that have delayed clinical benefits. The mechanism of action of ketamine is currently unclear but one hypothesis is that it may involve neuropsychological effects mediated through modulation of affective biases (where cognitive processes such as learning and memory and decision-making are modified by emotional state).

Preclinical validation of the micropipette-guided drug administration (MDA) method in the maternal immune activation model of neurodevelopmental disorders.

Pharmacological treatments in laboratory rodents remain a cornerstone of preclinical psychopharmacological research and drug development. There are numerous ways in which acute or chronic pharmacological treatments can be implemented, with each method having certain advantages and drawbacks. Here, we describe and validate a novel treatment method in mice, which we refer to as the micropipette-guided drug administration (MDA) procedure.

Antimanic Efficacy of a Novel Kv3 Potassium Channel Modulator.

Kv3.1 and Kv3.2 voltage-gated potassium channels are expressed on parvalbumin-positive GABAergic interneurons in corticolimbic brain regions and contribute to high-frequency neural firing.

GSK356278, a potent, selective, brain-penetrant phosphodiesterase 4 inhibitor that demonstrates anxiolytic and cognition-enhancing effects without inducing side effects in preclinical species.

Small molecule phosphodiesterase (PDE) 4 inhibitors have long been known to show therapeutic benefit in various preclinical models of psychiatric and neurologic diseases because of their ability to elevate cAMP in various cell types of the central nervous system. Despite the registration of the first PDE4 inhibitor, roflumilast, for the treatment of chronic obstructive pulmonary disease, the therapeutic potential of PDE4 inhibitors in neurologic diseases has never been fulfilled in the clinic due to severe dose-limiting side effects such as nausea and vomiting. In this study, we describe the detailed pharmacological characterization of GSK356278 [5-(5-((2,4-dimethylthiazol-5-yl)methyl)-1,3,4-oxadiazol-2-yl)-1-ethyl-N-(tetrahydro-2H-pyran-4-yl)-1H-pyrazolo[3,4-b]pyridin-4-amine], a potent, selective, and brain-penetrant PDE4 inhibitor that shows a superior therapeutic index to both rolipram and roflumilast in various preclinical species and has potential for further development in the clinic for the treatment of psychiatric and neurologic diseases.

Social defeat and isolation induce clear signs of a depression-like state, but modest cardiac alterations in wild-type rats.

Adverse social environments play a relevant role in the onset and progression of mood disorders. On the other hand, depression is an independent risk factor for cardiovascular morbidity. This study was aimed at (i) corroborating the validity of a rat model of depression based on a negative social episode followed by social isolation and (ii) verifying its impact on cardiac function and structure.

Distinct receptor subtypes mediate arginine vasopressin-dependent ACTH release and intracellular calcium mobilization in rat pituitary cells.

In the present study, adrenocorticotropic hormone (ACTH) release and intracellular calcium ([Ca(2+)](i)) increase induced by arginine vasopressin (AVP) were characterized in collagenase-dispersed and 3-day cultured rat anterior pituitary cells. AVP and the selective vasopressin V(1b) receptor agonist, [1-deamino-4-cyclohexylalanine]AVP (d[Cha(4)]AVP) induced ACTH release with nanomolar potencies in both cell preparations, and produced a maximal stimulation that was about 1.5 fold greater in the 3-day cultured cells, indicating that the vasopressin V(1b) receptor-ACTH release pathway is enhanced over time in culture.

Effect of the p38 MAPK inhibitor SB-239063 on Lipopolysaccharide-induced psychomotor retardation and peripheral biomarker alterations in rats.

Lipopolysaccharide (LPS) administration in rats induces a characteristic syndrome termed 'sickness behavior', including profound changes on locomotor activity and circulating stress and inflammatory mediators. The aim of the present investigation was to evaluate whether the behavioral and the peripheral biomarker responses induced by LPS could be modified by acute treatment with the p38 mitogen-activated protein kinase inhibitor SB-239063. Male Sprague-Dawley rats were treated orally either with vehicle or SB-239063 (3, 10 and 30 mg/kg) 1h before an intraperitoneal injection of either saline or LPS 125 μg/kg.

A role for BDNF/TrkB signaling in behavioral and physiological consequences of social defeat stress.

Accumulating evidences underlie the importance of the interplay between environmental and genetic factors in contributing to the risk to develop mental illness. Brain-derived neurotrophic factor (BDNF) and its Tyrosine receptor kinase B (TrkB) receptor play a fundamental contribution to brain development and plastic adaptations to life events. In the present study, the potential for the BDNF/TrkB contribution in increasing vulnerability to negative social experiences was assessed by subjecting TrkB.

The characterization of a novel V1b antagonist lead series.

The SAR around a V1b antagonist HTS hit 3 was explored to produce a series of thiazole sulfonamides as a lead series with selectivity over the related V1 and oxytocin receptors.

Neuropeptide Y-Y2 receptor knockout mice: influence of genetic background on anxiety-related behaviors.

Neuropeptide Y (NPY) has been extensively studied in relation to anxiety and depression but of the seven NPY receptors known to date, it is not yet clear which one is mainly involved in mediating its effects in emotional behavior. Mice lacking the NPY-Y2 receptors were previously shown to be less anxious due to their improved ability to cope with stressful situations. In the present study, the behavioral phenotype including the response to challenges was analyzed in NPY-Y2 knockout (KO) mice backcrossed in to congenic C57BL/6 background.

5-{2-[4-(2-methyl-5-quinolinyl)-1-piperazinyl]ethyl}-2(1H)-quinolinones and 3,4-dihydro-2(1H)-quinolinones: dual-acting 5-HT1 receptor antagonists and serotonin reuptake inhibitors. Part 3.

5-{2-[4-(2-Methyl-5-quinolinyl)-1-piperazinyl]ethyl}-2(1H)-quinolinones and 3,4-dihydro-2(1H)-quinolinones have been identified with different combinations of 5-HT(1) autoreceptor antagonist and hSerT potencies and excellent rat PK profiles. The availability of tool compounds with a range of profiles at targets known to play a key role in the control of synaptic 5-HT levels will allow exploration of different pharmacological profiles in a range of animal behavioral and disease models.

Strain-specific outcomes of repeated social defeat and chronic fluoxetine treatment in the mouse.

Social stress is a risk factor for affective disorders in vulnerable individuals. Although the biological nature of stress susceptibility/resilience remains to be elucidated, genetic variation is considered amongst the principal contributors to brain disorders. Furthermore, genetic predisposition may be determinant for the therapeutic outcome, as proposed for antidepressant treatments.

Pyrrolo[1,2-a]pyrazine and pyrazolo[1,5-a]pyrazine: novel, potent, and selective series of Vasopressin 1b receptor antagonists.

Novel series of pyrrole-pyrazinone and pyrazole-pyrazinone have been identified as potent and selective Vasopressin(1b) receptor antagonists. Exploration of the substitution pattern around the core of these templates allowed generation of compounds with high inhibitory potency at the Vasopressin(1b) receptor, including examples that showed good selectivity with respect to Vasopressin(1a), Vasopressin(2), and Oxytocin receptor subtypes.

Different susceptibility to social defeat stress of BalbC and C57BL6/J mice.

Social stress may precipitate psychopathological disorders in susceptible individuals. The present experiments were focused on the biology beyond the differential susceptibility to social stress. Social defeat, an ethologically relevant stressor known to elicit different coping strategies, was used in two mouse strains differing for baseline emotionality, such as C57BL6/J and BalbC.

Functional role of Calcium-stimulated adenylyl cyclase 8 in adaptations to psychological stressors in the mouse: implications for mood disorders.

The Ca(2+)/calmodulin stimulated adenylyl cylcase 8 (AC8) is a pure Ca(2+) sensor, catalyzing the conversion of ATP to cAMP, with a critical role in neuronal plasticity. A role for AC8 in modulating complex behavioral outcomes has been demonstrated in AC8 knock out (KO) mouse models in which anxiety-like responses were differentially modulated following repeated stress experiences, suggesting an involvement of AC8 in stress adaptation and mood disorders. To further investigate the role of this enzyme in phenotypes relevant for psychiatric conditions, AC8 KO mice were assessed for baseline behavioral and hormonal parameters, responses to repeated restraint stress experience, and long-term effects of chronic social defeat stress.

Design and synthesis of novel tricyclic benzoxazines as potent 5-HT(1A/B/D) receptor antagonists leading to the discovery of 6-{2-[4-(2-methyl-5-quinolinyl)-1-piperazinyl]ethyl}-4H-imidazo[5,1-c][1,4]benzoxazine-3-carboxamide (GSK588045).

Bioisoteric replacement of the metabolically labile N-methyl amide group of a series of benzoxazinones with small heterocyclic rings has led to novel series of fused tricyclic benzoxazines which are potent 5-HT(1A/B/D) receptor antagonists with and without concomitant human serotonin transporter (hSerT) activity. Optimizing against multiple parameters in parallel identified 6-{2-[4-(2-methyl-5-quinolinyl)-1-piperazinyl]ethyl}-4H-imidazo[5,1-c][1,4]benzoxazine-3-carboxamide (GSK588045) as a potent 5-HT(1A/B/D) receptor antagonist with a high degree of selectivity over human ether-a-go-go related gene (hERG) potassium channels, favorable pharmacokinetics, and excellent activity in vivo in rodent pharmacodynamic (PD) models. On the basis of its outstanding overall profile, this compound was progressed as a clinical candidate with the ultimate aim to assess its potential as a faster acting antidepressant/anxiolytic with reduced side-effect burden.

6-(3,4-dichlorophenyl)-1-[(methyloxy)methyl]-3-azabicyclo[4.1.0]heptane: a new potent and selective triple reuptake inhibitor.

A pharmacophore model for triple reuptake inhibitors and the new class of 1-(aryl)-6-[alkoxyalkyl]-3-azabicyclo[3.1.0]hexanes were recently reported.

1-(Aryl)-6-[alkoxyalkyl]-3-azabicyclo[3.1.0]hexanes and 6-(aryl)-6-[alkoxyalkyl]-3-azabicyclo[3.1.0]hexanes: a new series of potent and selective triple reuptake inhibitors.

The discovery of new highly potent and selective triple reuptake inhibitors is reported. The new classes of 1-(aryl)-6-[alkoxyalkyl]-3-azabicyclo[3.1.