Electronic Structure and Coexistence of Superconductivity with Magnetism in RbEuFe4As4

In the novel stoichiometric iron-based material RbEuFe4As4, superconductivity coexists with a peculiar long-range magnetic order of Eu 4f states. Using angle-resolved photoemission spectroscopy, we reveal a complex three-dimensional electronic structure and compare it with density functional theory calculations. Multiple super-conducting gaps were measured on various sheets of the Fermi surface. High-resolution resonant photoemission spectroscopy reveals magnetic order of the Eu 4f states deep into the superconducting phase. Both the absolute values and the anisotropy of the superconducting gaps are remarkably similar to the sibling compound without Eu, indicating that Eu magnetism does not affect the pairing of electrons. A complete decoupling between Fe-and Eu-derived states was established from their evolution with temperature, thus unambiguously demonstrating that superconducting and a long-range magnetic orders exist independently from each other. The established electronic structure of RbEuFe4As4 opens opportunities for the future studies of the highly unorthodox electron pairing and phase competition in this family of iron-based superconductors with doping.We thank Matthew Watson for his critical reading of the manuscript. We thank Diamond Light Source for access to beamline I05 (Proposal No. SI15074 and No. SI19041) that contributed to the results presented here. Work was done using equipment from the LPI Shared Facility Center. K.S.P. and V.M.P. acknowledge support by the Russian Scientific Foundation (RSF Project No. 21-12-00394). A.V.S. and A.S.U. acknowledge support by the Russian Foundation for Basic Research (Project No. 21-52-12043). E.V.C. acknowledges funding by Saint Petersburg State University project for scientific investigations (ID No. 73028629). S.V.E. acknowledges support from the government research assignment for ISPMS SB RAS (Project FWRW-2019-0032). R.V. acknowledges funding by the Deutsche Forschungsgemeinschaft (DFG) TRR 288 (Project A05). V.B. thanks the Goethe University Frankfurt for computational resources and Daniel Guterding for providing the FS plotting software. K.K. thanks M. Valvidares, J. Herrero, H. B. Vasili, S. Agrestini, and N. Brookes for their support during the XMCD experiment at ALBA via IHR Proposal 2019063615. D.V.V. also acknowledges support from the Spanish Ministry of Economy (MAT-2017-88374-P

Adenosine A1 receptor: Functional receptor-receptor interactions in the brain

Over the past decade, many lines of investigation have shown that receptor-mediated signaling exhibits greater diversity than previously appreciated. Signal diversity arises from numerous factors, which include the formation of receptor dimers and interplay between different receptors. Using adenosine A1 receptors as a paradigm of G protein-coupled receptors, this review focuses on how receptor-receptor interactions may contribute to regulation of the synaptic transmission within the central nervous system. The interactions with metabotropic dopamine, adenosine A2A, A3, neuropeptide Y, and purinergic P2Y1 receptors will be described in the first part. The second part deals with interactions between A1Rs and ionotropic receptors, especially GABAA, NMDA, and P2X receptors as well as ATP-sensitive K+ channels. Finally, the review will discuss new approaches towards treating neurological disorders

Suchtentstehung, Rueckfall und Rueckfallprophylaxe bei Alkoholismus; neurobiologisch-pharmakologische, psychologische und klinische Aspekte -Einfluss von Ethanol auf zentrale Katecholamin-Neurone Abschlussbericht

SIGLEAvailable from TIB Hannover: DtF QN1(94,29) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung und Forschung, Berlin (Germany)DEGerman

Cross-tolerance between systemically and locally applied ethanol at N-methyl-D-aspartate receptors of rat locus coeruleus neurons in brain slices

Intracellular recordings were made in a pontine slice preparation of the rat brain containing the nucleus locus coeruleus (LC). Ethanol (100 mM) inhibited depolarizing responses to pressure-applied NMDA to a similar extent in LC neurons of ethanol-naive rats, and rats treated for 14 days with ethanol (3 g/kg daily, i.p.) or equicaloric amounts of saccharose. Brain slices were prepared 4 h after the last injection. In subsequent experiments, ethanol (10 mM) was continuously present in the superfusion medium in order to mimic a steady blood concentration. Under these conditions, ethanol (100 mM) still continued to inhibit the NMDA-induced depolarization in brain slices from untreated rats, but was ineffective in brain slices of ethanol-treated rats. Bath-applied NMDA (30 #mu#M) caused a similar depolarization in LC neurons of untreated animals (both in the presence and absence of 10 mM ethanol in the medium) and saccharose-treated animals. In LC neurons of ethanol-treated rats, NMDA (30 muM) was less active. However, this difference disappeared, when 10 mM ethanol was continuously present in the medium. By contrast, the effect of bath-applied #alpha#,#beta#-meATP (30 #mu#M) was not altered by the ethanol treatment of rats. In conclusion, cross-tolerance between systematically and locally applied ethanol could be documented only when the in vitro withdrawal was prevented by adding a low concentration of ethanol to the superfusion medium. (orig.)SIGLEAvailable from TIB Hannover: F00B719 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung und Forschung (BMBF), Bonn (Germany)DEGerman

Taurine-Induced Long-Lasting Enhancement of Synaptic Transmission in Mice: Role of Transporters

Taurine, a major osmolyte in the brain evokes a long-lasting enhancement (LLETAU) of synaptic transmission in hippocampal and cortico-striatal slices. Hippocampal LLETAU was abolished by the GABA uptake blocker nipecotic acid (NPA) but not by the taurine-uptake inhibitor guanidinoethyl sulphonate (GES). Striatal LLETAU was sensitive to GES but not to NPA. Semiquantitative PCR analysis and immunohistochemistry revealed that taurine transporter expression is significantly higher in the striatum than in the hippocampus. Taurine transporter-deficient mice displayed very low taurine levels in both structures and a low ability to develop LLETAU in the striatum, but not in the hippocampus. The different mechanisms of taurine-induced synaptic plasticity may reflect the different vulnerabilities of these brain regions under pathological conditions that are accompanied by osmotic changes such as hepatic encephalopathy