Involvement of the accumbal osteopontin-interacting transmembrane protein 168 in methamphetamine-induced place preference and hyperlocomotion in mice

Chronic exposure to methamphetamine causes adaptive changes in brain, which underlie dependence symptoms. We have found that the transmembrane protein 168 (TMEM168) is overexpressed in the nucleus accumbens of mice upon repeated methamphetamine administration. Here, we firstly demonstrate the inhibitory effect of TMEM168 on methamphetamine-induced behavioral changes in mice, and attempt to elucidate the mechanism of this inhibition. We overexpressed TMEM168 in the nucleus accumbens of mice by using an adeno-associated virus vector (NAc-TMEM mice). Methamphetamine-induced hyperlocomotion and conditioned place preference were attenuated in NAc-TMEM mice. Additionally, methamphetamine-induced extracellular dopamine elevation was suppressed in the nucleus accumbens of NAc-TMEM mice. Next, we identified extracellular matrix protein osteopontin as an interacting partner of TMEM168, by conducting immunoprecipitation in cultured COS-7 cells. TMEM168 overexpression in COS-7 cells induced the enhancement of extracellular and intracellular osteopontin. Similarly, osteopontin enhancement was also observed in the nucleus accumbens of NAc-TMEM mice, in in vivo studies. Furthermore, the infusion of osteopontin proteins into the nucleus accumbens of mice was found to inhibit methamphetamine-induced hyperlocomotion and conditioned place preference. Our studies suggest that the TMEM168-regulated osteopontin system is a novel target pathway for the therapy of methamphetamine dependence, via regulating the dopaminergic function in the nucleus accumbens

Rate Constant and Anti-oxidative Activity toward Hydroxyl Radicals; UV Irradiation

The anti-oxidative activity toward hydroxyl radicals was expressed by the reaction rate constant. Rate constants were presented for basic organic substances and reducing reagents. Hydroxyl radicals were generated by UV-irradiation of hydrogen peroxide. The pH was controlled through the reaction in the range 6.5-7.0. The dependence on the concentration of anti-oxidative substances was so small that the validity of the theoretical analysis was guaranteed

A mixed-valent metal–organic ladder linked by pyrazine

We report the synthesis, characterization, and electronic state of a novel mixed-valent metal-organic ladder (MOL) linked by pyrazine (pz). Single-crystal x-ray studies revealed that the MOL has a two-legged ladder-shaped framework, which is composed of a pz-connected Pt dimer with bridging Br ions. The electronic state of the MOL was investigated using x-ray and spectroscopic techniques; the MOL was found to have an electronic state that corresponds to the mixed-valence state of Pt(II)and Pt-IV. Furthermore, the intervalence charge transfer energy of the MOL has lower than that expected from the tendency of a similar halogen-bridged mixed-valence MOL owing to its unique 'zig-zag'-shaped legs. These results provide a new insight into the physical and electronic properties of MOL systems

Perception of Self-Moving Speed in Different Visual Cue and Viewpoint Conditions in Virtual Reality Environment

The perception of geometric cues in virtual spaces differs from that in actual spaces due to the reduced amount of information available in virtual spaces. To investigate the perception of own motion speed in virtual spaces, we conducted a user study involving 30 participants. We manipulated the amount and type of visual information and the viewpoint (i.e., first- or third-person perspective) in the virtual space, and investigated the subjective speed perception in a broad speed range using the psychophysical method of magnitude estimation. We investigated three types of virtual hallways with different scenery: the bleak hallway with little visual information, the hallway filled with objects with easily predictable dimensions, and the hallway with a textured wall that provided greater optical flows but little dimensional cues. Our results show that the speed was perceived to be slower in the bleak hallway than in the other hallways at some speed levels for both the first- and third-person perspective conditions. For the first-person perspective condition, the virtual space with the larger amount of dimensional information could lead to a more linear or accurate speed perception. In the third-person perspective condition, the speed perception was more linear than in the first-person perspective condition for the bleak and textured-wall conditions, and the differences in linearity between different hallway conditions diminished. Designers of virtual reality content need to know these properties of speed perception in virtual spaces

Observation of thermoacoustic shock waves in a resonance tube

This paper reports thermally induced shock waves observed in an acoustic resonance tube. Self-sustained oscillations of a gas column were created by imposing an axial temperature gradient on the short stack of plates installed in the resonance tube filled with air at atmospheric pressure. The tube length and axial position of the stack were examined so as to make the acoustic amplitude of the gas oscillations maximum. The periodic shock wave was observed when the acoustic pressure amplitude reached 8.3 kPa at the fundamental frequency. Measurements of the acoustic intensity show that the energy absorption in the stack region with the temperature gradient tends to prevent the nonlinear excitation of harmonic oscillations, which explains why the shock waves had been unfavorable in the resonance tube thermoacoustic systems

Neutral-Type One-Dimensional Mixed-Valence Halogen-Bridged Platinum Chain Complexes with Large Charge-Transfer Band Gaps

One-dimensional (1D) electronic systems have attracted significant attention for a long time because of their various physical properties. Among 1D electronic systems, 1D halogen-bridged mixed-valence transition-metal complexes (the so-called MX chains) have been thoroughly studied owing to designable structures and electronic states. Here, we report the syntheses, structures, and electronic properties of three kinds of novel neutral MX-chain complexes. The crystal structures consist of 1D chains of Pt–X repeating units with (1<i>R</i>,2<i>R</i>)-(−)-diaminocychlohexane and CN^– in-plane ligands. Because of the absence of a counteranion, the neutral MX chains have short interchain distances, so that strong interchain electronic interaction is expected. Resonance Raman spectra and diffuse-reflectance UV–vis spectra indicate that their electronic states are mixed-valence states (charge-density-wave state: Pt²⁺···X–Pt⁴⁺–X···Pt²⁺···X–Pt⁴⁺–X···). In addition, the relationship between the intervalence charge-transfer (IVCT) band gap and the degree of distortion of the 1D chain shows that the neutral MX chains have a larger IVCT band gap than that of cationic MX-chain complexes. These results provide new insight into the physical and electronic properties of 1D chain compounds

Involvement of the accumbal osteopontin-interacting transmembrane protein 168 in methamphetamine-induced place preference and hyperlocomotion in mice

Abstract Chronic exposure to methamphetamine causes adaptive changes in brain, which underlie dependence symptoms. We have found that the transmembrane protein 168 (TMEM168) is overexpressed in the nucleus accumbens of mice upon repeated methamphetamine administration. Here, we firstly demonstrate the inhibitory effect of TMEM168 on methamphetamine-induced behavioral changes in mice, and attempt to elucidate the mechanism of this inhibition. We overexpressed TMEM168 in the nucleus accumbens of mice by using an adeno-associated virus vector (NAc-TMEM mice). Methamphetamine-induced hyperlocomotion and conditioned place preference were attenuated in NAc-TMEM mice. Additionally, methamphetamine-induced extracellular dopamine elevation was suppressed in the nucleus accumbens of NAc-TMEM mice. Next, we identified extracellular matrix protein osteopontin as an interacting partner of TMEM168, by conducting immunoprecipitation in cultured COS-7 cells. TMEM168 overexpression in COS-7 cells induced the enhancement of extracellular and intracellular osteopontin. Similarly, osteopontin enhancement was also observed in the nucleus accumbens of NAc-TMEM mice, in in vivo studies. Furthermore, the infusion of osteopontin proteins into the nucleus accumbens of mice was found to inhibit methamphetamine-induced hyperlocomotion and conditioned place preference. Our studies suggest that the TMEM168-regulated osteopontin system is a novel target pathway for the therapy of methamphetamine dependence, via regulating the dopaminergic function in the nucleus accumbens

Confined water-mediated high proton conduction in hydrophobic channel of a synthetic nanotube

ナノサイズの空間に閉じ込められた水が示す不思議な性質を実証 --高速で水素イオンを運ぶ水の状態を解明--. 京都大学プレスリリース. 2020-02-18.Water confined within one-dimensional (1D) hydrophobic nanochannels has attracted significant interest due to its unusual structure and dynamic properties. As a representative system, water-filled carbon nanotubes (CNTs) are generally studied, but direct observation of the crystal structure and proton transport is difficult for CNTs due to their poor crystallinity and high electron conduction. Here, we report the direct observation of a unique water-cluster structure and high proton conduction realized in a metal-organic nanotube, [Pt(dach)(bpy)Br]4(SO4)4·32H2O (dach: (1R, 2R)-(–)-1, 2-diaminocyclohexane; bpy: 4, 4’-bipyridine). In the crystalline state, a hydrogen-bonded ice nanotube composed of water tetramers and octamers is found within the hydrophobic nanochannel. Single-crystal impedance measurements along the channel direction reveal a high proton conduction of 10−2 Scm−1. Moreover, fast proton diffusion and continuous liquid-to-solid transition are confirmed using solid-state 1H-NMR measurements. Our study provides valuable insight into the structural and dynamical properties of confined water within 1D hydrophobic nanochannels