Further characterization of the GlyT-1 inhibitor Org25935 : anti-alcohol, neurobehavioral, and gene expression effects

The glycine transporter-1 inhibitor Org25935 is a promising candidate in a treatment concept for alcohol use disorder targeting the glycine system. Org25935 inhibits ethanol-induced dopamine elevation in brain reward regions and reduces ethanol intake in Wistar rats. This study aimed to further characterise the compound and used ethanol consumption, behavioral measures, and gene expression as parameters to investigate the effects in Wistar rats and, as pharmacogenetic comparison, Alko-Alcohol (AA) rats. Animals were provided limited access to ethanol in a two-bottle free-choice paradigm with daily drug administration. Acute effects of Org25935 were estimated using locomotor activity and neurobehavioral status. Effects on gene expression in Wistar rats were measured with qPCR. The higher but not the lower dose of Org25935 reduced alcohol intake in Wistar rats. Unexpectedly, Org25935 reduced both ethanol and water intake and induced strong CNS-depressive effects in AA-rats (withdrawn from further studies). Neurobehavioral effects by Org25935 differed between the strains (AA-rats towards sedation). Org25935 did not affect gene expression at the mRNA level in the glycine system of Wistar rats. The data indicate a small therapeutic range for the anti-alcohol properties of Org25935, a finding that may guide further evaluations of the clinical utility of GlyT-1 inhibitors. The results point to the importance of pharmacogenetic considerations when developing drugs for alcohol-related medical concerns. Despite the lack of successful clinical outcomes, to date, the heterogeneity of drug action of Org25935 and similar agents and the unmet medical need justify further studies of glycinergic compounds in alcohol use disorder.Peer reviewe

Expression of aldehyde dehydrogenase family 1, member A3 in glycogen trophoblast cells of the murine placenta

Introduction: Retinoic acid (RA) signaling is a well known regulator of trophoblast differentiation and placental development, and maternal decidual cells are recognized as the source of much of this RA. We explored possible trophoblast-derived sources of RA by examining the expression of RA synthesis enzymes in the developing mouse placenta, as well as addressed potential sites of RA action by examining the ontogeny of gene expression for other RA metabolizing and receptor genes. Furthermore, we investigated the effects of endogenous RA production on trophoblast differentiation

Study of neurons and glial cells in the trigeminal motor nucleus and inhibitory neurons projecting to the trigeminal motor nucleus

ラット三叉神経運動核におけるニューロン-グリア細胞構築と三叉神経運動核に投射する抑制性ニューロンについて検討した。Wistar系ラットを用いた。GFAP陽性細胞は三叉神経運動核(Vm)の周囲の小細胞性網様体に多数が観察された。S100タンパク陽性細胞はVmに多数が標識され、特に顎二腹筋支配ニューロンを含む腹内側亜核に密に分布した。三叉神経上核(sV)にはGAD-67とGLYT-2の遺伝子発現細胞を認め、その中のいくつかの細胞において両方の遺伝子を発現していた。GAD-67とGLYT-2発現細胞の形態は、ともに紡錘形や楕円形を示したが、GLYT-2を発現する細胞は大型が多かった。神奈川歯科大学201

Using the Salop Circle to Study Scale Effects in Schumpeterian Growth Models: Why Inter-sectoral Knowledge Diffusion Matters

This paper analyzes the link between the fact that fully endogenous growth models exhibit (or not) the non-desirable scale effects property and assumptions regarding the intensity of knowledge diffusion. In that respect, we extend a standard Schumpeterian growth model by introducing explicitly knowledge diffusion over a Salop (1979) circle: a continuum of sectors simultaneously sending and receiving knowledge is located over the circle. The link between knowledge diffusion and scale effects stems from the fact that the more diffusion spreads with the size of the economy, the larger the pools of knowledge used by each sector’s R&D activity are, the higher the marginal productivity of labor in R&D is, and eventually the higher the growth rate is. The paper tackles the apparent following paradox. Knowledge diffusion seems to lead to scale effects; however, the former is empirically desirable while the latter is not. Our first basic result is that a sufficient condition to have a scale-invariant fully endogenous growth model is to assume no inter-sectoral knowledge diffusion. However, this assumption is not empirically reasonable. We overcome the aforementioned paradox by showing that the absence of diffusion is not a necessary condition to suppress scale effects. More precisely, we determine sets of reasonable assumptions on knowledge diffusion under which one can obtain fully endogenous growth models complying with most undeniable empirical facts - namely the absence of significant scale effects, the impact of public policies on the growth rate, and somehow realistic interactions among sectors R&D activities (including the occurrence of GPTs)

The Lindahl equilibrium in Schumpeterian growth models

What is the social value of innovations in Schumpeterian growth models? This issue is tackled by introducing the concept of Lindahl equilibrium in a standard endogenous growth model with vertical innovations which is extended by explicitly considering knowledge diffusion. Assuming that knowledge diffuses on a Salop (1979) circle allows us to formalize the creation of the pools of knowledge in which research and development (R&D) activities draw from to produce innovations. Within this model, we compare two equilibria. The standard Schumpeterian equilibrium à la Aghion & Howitt (1992) is mainly characterized by incomplete markets since knowledge is not priced. It provides the usual private value of innovations. The Lindahl equilibrium is a benchmark enabling us to compute the system of prices that sustains the first-best social optimum, and thus to define and to determine analytically the social value of innovations. It provides a suitable methodology for revisiting issues involving the presence of knowledge, often studied in the industrial organization and endogenous growth literatures. This comparison sheds a new light on the consequences of non-rivalry of knowledge and of market incompleteness on innovators’ behavior in the Schumpeterian equilibrium. We notably revisit the issues of Pareto sub-optimality and of R&D incentives in presence of cumulative innovations. Basically, the key externality triggered by market incompleteness implies that knowledge creation is indirectly funded by means of intellectual property rights on rival goods embodying knowledge. Therefore, because the private value of innovations differs from the social one, innovators are not given the optimal incentives

Probing the Modulation of Acute Ethanol Intoxication by Pharmacological Manipulation of the NMDAR Glycine Co-Agonist Site

BACKGROUND: Stimulating the glycine(B) binding site on the N-methyl-D-aspartate receptor (NMDAR) has been proposed as a novel mechanism for modulating behavioral effects of ethanol (EtOH) that are mediated via the NMDAR, including acute intoxication. Here, we pharmacologically interrogated this hypothesis in mice. METHODS: Effects of systemic injection of the glycine(B) agonist, D-serine, the GlyT-1 glycine transporter inhibitor, ALX-5407, and the glycine(B) antagonist, L-701,324, were tested for effects on EtOH-induced ataxia, hypothermia, loss of righting reflex duration (LORR) in C57BL/6J (B6) and 129S1/SvImJ (S1) inbred mice. Effects of the glycine(B) partial agonist, D-cycloserine, the GlyT-1 inhibitor, NFPS, and the glycine(B) antagonist, DCKA, on EtOH-induced LORR duration were also tested. Interaction effects on EtOH-induced LORR duration were examined via combined treatment with D-serine and ALX-5407, D-serine and MK-801, D-serine and L-701,324, as well as L-701,324 and ALX-5407, in B6 mice, as D-serine in GluN2A and PSD-95 KO mice. The effect of dietary depletion of Magnesium (Mg), an element which interacts the glycine(B) site, was also tested. RESULTS: Neither D-serine, D-cycloserine, ALX-5407, nor NFPS significantly affected EtOH intoxication on any of the measures or strains studied. L-701,324, but not DCKA, dose-dependently potentiated the ataxia-inducing effects of EtOH and increased EtOH-induced (but not pentobarbital-induced) LORR duration. D-serine did not have interactive effects on EtOH-induced LORR duration when combined with ALX-5407. The EtOH-potentiating effects of L-701,324, but not MK-801, on LORR duration were prevented by D-serine, but not ALX-5407. Mg depletion potentiated LORR duration in B6 mice and was lethal in a large proportion of S1 mice. CONCLUSIONS: Glycine(B) site activation failed to produce the hypothesized reduction in EtOH intoxication across a range of measures and genetic strains, but blockade of the glycine(B) site potentiated EtOH intoxication. These data suggest endogenous activity at the glycine(B) opposes EtOH intoxication, but it may be difficult to pharmacologically augment this action, at least in non-dependent subjects, perhaps due to physiological saturation of the glycine(B) site

Synthesis of tetrazole analogs of amino acids using Fmoc chemistry: isolation of amino free tetrazoles and their incorporation into peptides

An efficient synthesis of tetrazole analogs of amino acids starting from Nα-​Fmoc amino acid (Fmoc = 9-​fluorenylmethoxycarbonyl) in a three-​step protocol is reported. The free amino tetrazoles were obtained in good yields and with excellent purity after removal of the Fmoc group. The synthesis of analogs of aspartic and glutamic acids in which the 5-​tetrazolyl moiety is inserted at the β​/γ carboxyl group starting from Fmoc-​Asn and Fmoc-​Gln and the incorporation of these tetrazoles into peptides are also described

Molecular and fossil evidence place the origin of cichlid fishes long after Gondwanan rifting.

Cichlid fishes are a key model system in the study of adaptive radiation, speciation and evolutionary developmental biology. More than 1600 cichlid species inhabit freshwater and marginal marine environments across several southern landmasses. This distributional pattern, combined with parallels between cichlid phylogeny and sequences of Mesozoic continental rifting, has led to the widely accepted hypothesis that cichlids are an ancient group whose major biogeographic patterns arose from Gondwanan vicariance. Although the Early Cretaceous (ca 135 Ma) divergence of living cichlids demanded by the vicariance model now represents a key calibration for teleost molecular clocks, this putative split pre-dates the oldest cichlid fossils by nearly 90 Myr. Here, we provide independent palaeontological and relaxed-molecular-clock estimates for the time of cichlid origin that collectively reject the antiquity of the group required by the Gondwanan vicariance scenario. The distribution of cichlid fossil horizons, the age of stratigraphically consistent outgroup lineages to cichlids and relaxed-clock analysis of a DNA sequence dataset consisting of 10 nuclear genes all deliver overlapping estimates for crown cichlid origin centred on the Palaeocene (ca 65-57 Ma), substantially post-dating the tectonic fragmentation of Gondwana. Our results provide a revised macroevolutionary time scale for cichlids, imply a role for dispersal in generating the observed geographical distribution of this important model clade and add to a growing debate that questions the dominance of the vicariance paradigm of historical biogeography

Restoration of Sp4 in Forebrain GABAergic Neurons Rescues Hypersensitivity to Ketamine in Sp4 Hypomorphic Mice.

BackgroundKetamine produces schizophrenia-like behavioral phenotypes in healthy people. Prolonged ketamine effects and exacerbation of symptoms after the administration of ketamine have been observed in patients with schizophrenia. More recently, ketamine has been used as a potent antidepressant to treat patients with major depression. The genes and neurons that regulate behavioral responses to ketamine, however, remain poorly understood. Sp4 is a transcription factor for which gene expression is restricted to neuronal cells in the brain. Our previous studies demonstrated that Sp4 hypomorphic mice display several behavioral phenotypes relevant to psychiatric disorders, consistent with human SP4 gene associations with schizophrenia, bipolar disorder, and major depression. Among those behavioral phenotypes, hypersensitivity to ketamine-induced hyperlocomotion has been observed in Sp4 hypomorphic mice.MethodsIn the present study, we used the Cre-LoxP system to restore Sp4 gene expression, specifically in either forebrain excitatory or GABAergic inhibitory neurons in Sp4 hypomorphic mice. Mouse behavioral phenotypes related to psychiatric disorders were examined in these distinct rescue mice.ResultsRestoration of Sp4 in forebrain excitatory neurons did not rescue deficient sensorimotor gating nor ketamine-induced hyperlocomotion. Restoration of Sp4 in forebrain GABAergic neurons, however, rescued ketamine-induced hyperlocomotion, but did not rescue deficient sensorimotor gating.ConclusionsOur studies suggest that the Sp4 gene in forebrain GABAergic neurons regulates ketamine-induced hyperlocomotion

Astrocytic processes compensate for the apparent lack of GABA transporters in the axon terminals of cerebellar Purkinje cells.

The aim of the present study was to evaluate the expression of two high affinity GABA transporters (GAT-1 and GAT-3) in the rat cerebellum using immunocytochemistry and affinity purified antibodies. GAT-1 immunoreactivity was prominent in punctate structures and axons in all layers of the cerebellar cortex, and was especially prominent around the somata of Purkinje cells. In contrast, the deep cerebellar nuclei showed few if any GAT-1 immunoreactive puncta. Weak GAT-3 immunoreactive processes were present in the cerebellar cortex, whereas GAT-3 immunostaining was prominent around the somata of neurons in the deep cerebellar nuclei. Electron microscopic preparations of the cerebellar cortex demonstrated that GAT-1 immunoreactive axon terminals formed symmetric synapses with somata, axon initial segments and dendrites of Purkinje cells and the dendrites of granule cells. Astrocytic processes in the cerebellar cortex were also immunolabeled for GAT-1. However, Purkinje cell axon terminals that formed symmetric synapses with neurons in the deep cerebellar nuclei lacked GAT-1 immunoreactivity. Instead, weak GAT-1 and strong GAT-3 immunoreactivities were expressed by astrocytic processes that enveloped the Purkinje cell axon terminals. In addition, GAT-3-immunoreactivity appeared in astrocytic processes in the cerebellar cortex. These observations demonstrate that GAT-1 is localized to axon terminals of three of the four neuronal types that were previously established as being GABAergic, i.e. basket, stellate and Golgi cells. GAT-1 and GAT-3 are expressed by astrocytes. The failure to identify a GABA transporter in Purkinje cells is consistent with previous data that indicated that Purkinje cells lacked terminal uptake mechanisms for GABA. The individual glial envelopment of Purkinje cell axon terminals in the deep cerebellar nuclei and the dense immunostaining of GAT-3, and to a lesser extent GAT-1, expressed by astrocytic processes provide a compensatory mechanism for the removal of GABA from the synaptic cleft of synapses formed by Purkinje cell axon terminals