In vivo photocontrol of orexin receptors with a nanomolar light-regulated analogue of orexin-B.

Orexinergic neurons are critically involved in regulating arousal, wakefulness, and appetite. Their dysfunction has been associated with sleeping disorders, and non-peptide drugs are currently being developed to treat insomnia and narcolepsy. Yet, no light-regulated agents are available to reversibly control their activity.

Liberal or Restrictive Transfusion Strategy in Patients with Traumatic Brain Injury.

Background: The effect of a liberal transfusion strategy as compared with a restrictive strategy on outcomes in critically ill patients with traumatic brain injury is unclear.

Methods: We randomly assigned adults with moderate or severe traumatic brain injury and anemia to receive transfusion of red cells according to a liberal strategy (transfusions initiated at a hemoglobin level of ≤10 g per deciliter) or a restrictive strategy (transfusions initiated at ≤7 g per deciliter). The primary outcome was an unfavorable outcome as assessed by the score on the Glasgow Outcome Scale-Extended at 6 months, which we categorized with the use of a sliding dichotomy that was based on the prognosis of each patient at baseline.

Characterization of tritiated JNJ-GluN2B-5 (3-[H] 1-(azetidin-1-yl)-2-(6-(4-fluoro-3-methyl-phenyl)pyrrolo[3,2-b]pyridin-1-yl)ethanone), a high affinity GluN2B radioligand with selectivity over sigma receptors.

Here, we describe the characterization of a radioligand selective for GluN2B-containing NMDA receptors, 3-[H] 1-(azetidin-1-yl)-2-(6-(4-fluoro-3-methyl-phenyl)pyrrolo[3,2-b]pyridin-1-yl)ethanone ([H]-JNJ- GluN2B-5). In rat cortical membranes, the compound bound to a single site, and the following kinetic parameters were measured; association rate constant K = 0.0066 ± 0.

Characterization of Selective M Acetylcholine Muscarinic Receptor Modulators on Dopamine Signaling in the Striatum.

The type-5 muscarinic acetylcholine receptor (mAChR, M) is almost exclusively expressed in dopamine (DA) neurons of the ventral tegmental area and substantia nigra pars compacta; therefore, they are ideally located to modulate DA signaling and underlying behaviors. However, the role of M in shaping DA release is still poorly characterized. In this study, we first quantitatively mapped the expression of M in different neurons of the mouse midbrain, then used voltammetry in mouse striatum to evaluate the effect of M-selective modulators on DA release.

Pharmacological characterization of the selective orexin-1 receptor antagonist JNJ-61393215 in healthy volunteers.

Background: Up to 40% of patients suffering from anxiety disorders do not benefit from currently available pharmacological treatments. Overactivity of the orexin-1 receptor (OX1R) has been implicated in anxiety- and panic-related states.

Aim & Methods: We investigated the pharmacokinetics and characterized the pharmacodynamic (PD) profile of the OX1R antagonist JNJ-61393215 using a battery of central nervous system assessments investigating relevant functional domains such as alertness, attention, (visuo)motor coordination, balance, subjective effects and resting-state electroencephalography in a single ascending dose placebo-controlled study in doses from 1 to 90 mg inclusive, assessing PD up to 10 h after dosing, safety and pharmacokinetic in 48 healthy male subjects.

Identification and characterization of select oxysterols as ligands for GPR17.

Background And Purpose: G-protein coupled receptor 17 (GPR17) is an orphan receptor involved in the process of myelination, due to its ability to inhibit the maturation of oligodendrocyte progenitor cells (OPCs) into myelinating oligodendrocytes. Despite multiple claims that the biological ligand has been identified, it remains an orphan receptor.

Experimental Approach: Seventy-seven oxysterols were screened in a cell-free [ S]GTPγS binding assay using membranes from cells expressing GPR17.

Discovery and SAR studies of 2-alkyl-3-phenyl-2,4,5,6,7,8-hexahydropyrazolo[3,4-d]azepines as 5-HT inhibitors leading to the identification of a clinical candidate.

We report here the synthesis and characterization of a dual 5-HT / 5-HT receptor antagonist 3-(4-Fluoro-phenyl)-2-isopropyl-2,4,5,6,7,8-hexahydro-1,2,6-triaza-azulene (4j). 4j is a high affinity 5-HT and 5-HT receptor ligand having a pK = 8.1 at both receptors.

Screening for modulators of neural network activity in 3D human iPSC-derived cortical spheroids.

Human induced Pluripotent Stem Cells (iPSCs) are a powerful tool to dissect the biology of complex human cell types such as those of the central nervous system (CNS). However, robust, high-throughput platforms for reliably measuring activity in human iPSC-derived neuronal cultures are lacking. Here, we assessed 3D cultures of cortical neurons and astrocytes displaying spontaneous, rhythmic, and highly synchronized neural activity that can be visualized as calcium oscillations on standard high-throughput fluorescent readers as a platform for CNS-based discovery efforts.

Substituted Azabicyclo[2.2.1]heptanes as Selective Orexin-1 Antagonists: Discovery of JNJ-54717793.

The orexin system consists of two neuropeptides (orexin-A and orexin-B) that exert their mode of action on two receptors (orexin-1 and orexin-2). While the role of the orexin-2 receptor is established as an important modulator of sleep wake states, the role of the orexin-1 receptor is believed to play a role in addiction, panic, or anxiety. In this manuscript, we describe the optimization of a nonselective substituted azabicyclo[2.

Translational evaluation of novel selective orexin-1 receptor antagonist JNJ-61393215 in an experimental model for panic in rodents and humans.

Orexin neurons originating in the perifornical and lateral hypothalamic area project to anxiety- and panic-associated neural circuitry, and are highly reactive to anxiogenic stimuli. Preclinical evidence suggests that the orexin system, and particularly the orexin-1 receptor (OX1R), may be involved in the pathophysiology of panic and anxiety. Selective OX1R antagonists thus may constitute a potential new treatment strategy for panic- and anxiety-related disorders.

Putative role of GPR139 on sleep modulation using pharmacological and genetic rodent models.

GPR139 is a G-protein coupled receptor expressed in circumventricular regions of the habenula and septum. Amino acids L-tryptophan and L-phenylalanine have been shown to activate GPR139 at physiologically relevant concentrations. The aim of the present study was to investigate the role of GPR139 on sleep modulation using pharmacological and genetic (GPR139 knockout mice, KO) rodent models.

Pharmacologic Characterization of JNJ-42226314, [1-(4-Fluorophenyl)indol-5-yl]-[3-[4-(thiazole-2-carbonyl)piperazin-1-yl]azetidin-1-yl]methanone, a Reversible, Selective, and Potent Monoacylglycerol Lipase Inhibitor.

The serine hydrolase monoacylglycerol lipase (MAGL) is the rate-limiting enzyme responsible for the degradation of the endocannabinoid 2-arachidonoylglycerol (2-AG) into arachidonic acid and glycerol. Inhibition of 2-AG degradation leads to elevation of 2-AG, the most abundant endogenous agonist of the cannabinoid receptors (CBs) CB1 and CB2. Activation of these receptors has demonstrated beneficial effects on mood, appetite, pain, and inflammation.

Low-value clinical practices in injury care: A scoping review and expert consultation survey.

Background: Tests and treatments that are not supported by evidence and could expose patients to unnecessary harm, referred to here as low-value clinical practices, consume up to 30% of health care resources. Choosing Wisely and other organizations have published lists of clinical practices to be avoided. However, few apply to injury and most are based uniquely on expert consensus.

GPR139 and Dopamine D2 Receptor Co-express in the Same Cells of the Brain and May Functionally Interact.

GPR139, a G-coupled receptor that is activated by the essential amino acids L-tryptophan and L-phenylalanine, is predominantly expressed in the brain and pituitary. The physiological function of GPR139 remains elusive despite the availability of pharmacological tool agonist compounds and knock-out mice. Whole tissue RNA sequencing data from human, mouse and rat tissues revealed that GPR139 and the dopamine D receptor (DRD2) exhibited some similarities in their distribution patterns in the brain and pituitary gland.

Characterization of a Selective, Orally Available, and Brain Penetrant Small Molecule GPR139 Agonist.

Recently, our group along with another demonstrated that GPR139 can be activated by L-phenylalanine (L-Phe) and L-tryptophan (L-Trp) at physiologically relevant concentrations. GPR139 is discretely expressed in brain, with highest expression in medial habenula. Not only are the endogenous ligands catecholamine/serotonin precursors, but GPR139 expressing areas can directly/indirectly regulate the activity of catecholamine/serotonin neurons.

Calcium Imaging Reveals That Cortisol Treatment Reduces the Number of Place Cells in Thy1-GCaMP6f Transgenic Mice.

The hippocampus, a structure essential for spatial navigation and memory undergoes anatomical and functional changes during chronic stress. Here, we investigate the effects of chronic stress on the ability of place cells to encode the neural representation of a linear track. To model physiological conditions of chronic stress on hippocampal function, transgenic mice expressing the genetically encoded calcium indicator GCaMP6f in CA1 pyramidal neurons were chronically administered with 40 μg/ml of cortisol for 8 weeks.

Mutagenesis of GPR139 reveals ways to create gain or loss of function receptors.

GPR139 is a Gq-coupled receptor activated by the essential amino acids L-tryptophan (L-Trp) and L-phenylalanine (L-Phe). We carried out mutagenesis studies of the human GPR139 receptor to identify the critical structural motifs required for GPR139 activation. We applied site-directed and high throughput random mutagenesis approaches using a double addition normalization strategy to identify novel GPR139 sequences coding receptors that have altered sensitivity to endogenous ligands.

Orexin Depolarizes Central Amygdala Neurons via Orexin Receptor 1, Phospholipase C and Sodium-Calcium Exchanger and Modulates Conditioned Fear.

Orexins (OX), also known as hypocretins, are excitatory neuropeptides with well-described roles in regulation of wakefulness, arousal, energy homeostasis, and anxiety. An additional and recently recognized role of OX is modulation of fear responses. We studied the OX neurons of the perifornical hypothalamus (PeF) which send projections to the amygdala, a region critical in fear learning and fear expression.

Utilizing Miniature Fluorescence Microscopy to Image Hippocampal Place Cell Ensemble Function in Thy1.GCaMP6f Transgenic Mice.

Imaging neuronal activity in awake behaving mice with miniature fluorescence microscopes requires the implementation of a variety of procedures. Surgeries are performed to gain access to the cell population of interest and to implant microscope components. After a recovery period, mice are trained to exhibit a desired behavior.

The Zinc Transporter SLC39A7 (ZIP7) Is Essential for Regulation of Cytosolic Zinc Levels.

Zinc homeostasis is a highly regulated process in mammalian cells that is critical for normal growth and development. Movement of zinc across cell compartments is controlled by two classes of transporters: Slc39a family members transport zinc into the cytosol from either the extracellular space or intracellular stores such as the endoplasmic reticulum (ER), whereas the SLC30A family mediates zinc efflux from the cytosol. In this study, we report that genetic ablation of SLC39A7 (ZIP7) results in decreased cytosolic zinc levels, increased ER zinc levels, impaired cell proliferation, and induction of ER stress.

Re-evaluation of Adrenocorticotropic Hormone and Melanocyte Stimulating Hormone Activation of GPR139 .

It is now well established that GPR139, a G-protein coupled receptor exclusively expressed in the brain and pituitary, is activated by the essential amino acids L-tryptophan (L-Trp) and L-phenylalanine (L-Phe) via G-coupling. The affinity and potency values of L-Trp and L-Phe are within the physiological concentration ranges of L-Trp and L-Phe. A recent paper suggests that adrenocorticotropic hormone (ACTH), α and β melanocyte stimulating hormones (α-MSH and β-MSH) and derivatives α-MSH/α-MSH can also activate GPR139 .

Evaluation of JNJ-54717793 a Novel Brain Penetrant Selective Orexin 1 Receptor Antagonist in Two Rat Models of Panic Attack Provocation.

Orexin neurons originating in the perifornical and lateral hypothalamic area are highly reactive to anxiogenic stimuli and have strong projections to anxiety and panic-associated circuitry. Recent studies support a role for the orexin system and in particular the orexin 1 receptor (OX1R) in coordinating an integrative stress response. However, no selective OX1R antagonist has been systematically tested in two preclinical models of using panicogenic stimuli that induce panic attack in the majority of people with panic disorder, namely an acute hypercapnia-panic provocation model and a model involving chronic inhibition of GABA synthesis in the perifornical hypothalamic area followed by intravenous sodium lactate infusion.

Selective Inhibition of Orexin-2 Receptors Prevents Stress-Induced ACTH Release in Mice.

Orexins peptides exert a prominent role in arousal-related processes including stress responding, by activating orexin-1 (OX1R) and orexin-2 (OX2R) receptors located widely throughout the brain. Stress or orexin administration stimulates hyperarousal, adrenocorticotropic hormone (ACTH) and corticosterone release, and selective OX1R blockade can attenuate several stress-induced behavioral and cardiovascular responses but not the hypothalamic-pituitary-adrenal (HPA) axis activation. As opposed to OX1R, OX2R are preferentially expressed in the paraventricular hypothalamic nucleus which is involved in the HPA axis regulation.

4-Methyl-6,7-dihydro-4H-triazolo[4,5-c]pyridine-Based P2X7 Receptor Antagonists: Optimization of Pharmacokinetic Properties Leading to the Identification of a Clinical Candidate.

The synthesis and preclinical characterization of novel 4-(R)-methyl-6,7-dihydro-4H-triazolo[4,5-c]pyridines that are potent and selective brain penetrant P2X7 antagonists are described. Optimization efforts based on previously disclosed unsubstituted 6,7-dihydro-4H-triazolo[4,5-c]pyridines, methyl substituted 5,6,7,8-tetrahydro[1,2,4]triazolo[4,3-a]pyrazines, and several other series lead to the identification of a series of 4-(R)-methyl-6,7-dihydro-4H-triazolo[4,5-c]pyridines that are selective P2X7 antagonists with potency at the rodent and human P2X7 ion channels. These novel P2X7 antagonists have suitable physicochemical properties, and several analogs have an excellent pharmacokinetic profile, good partitioning into the CNS and show robust in vivo target engagement after oral dosing.

Hospital length of stay following admission for traumatic brain injury in a Canadian integrated trauma system: A retrospective multicenter cohort study.

Background: Traumatic brain injury (TBI) is the leading cause of disability in children and young adults and costs CAD$3 billion annually in Canada. Stakeholders have expressed the urgent need to obtain information on resource use for TBI to improve the quality and efficiency of acute care in this patient population. We aimed to assess the components and determinants of hospital and ICU LOS for TBI admissions.