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  • 1
    Electronic Resource
    Electronic Resource
    Dynorphins directly inhibit neuronal nicotinic acetylcholine receptors in PC12 cells (2000)
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 12 (2000), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The authors have previously reported that dynorphin A (1–17), an endogenous kappa opioid agonist, inhibits the current mediated through neuronal nicotinic acetylcholine receptors (nAChRs) without the involvement of opioid receptors or G-proteins. We have further characterized this action to elucidate the mechanisms. The nicotine-induced current was studied in PC12 cells using patch-clamp techniques. In the whole-cell configuration, four kinds of dynorphins with different lengths, dynorphin A (1–17) (1–13) (2–13) and (1–8), similarly inhibited the nicotine-induced inward current at 1 μm and accelerated the current decay. The inhibition by dynorphin A (1–17) was not antagonized by the increasing concentrations of nicotine. The current–voltage relationship revealed that dynorphin's inhibition was voltage independent at the membrane potentials from −30 to −70 mV. The inhibition was not affected by pretreatment with pertussis toxin (PTX) or inclusion of staurosporine into the pipette solution. The inhibitory effect of dynorphin A (1–17) was well preserved in the outside-out patch configuration. Analysis of the nicotine-induced noise and single-channel kinetics revealed that dynorphin A(1–17) reduced open time without changing the amplitude of the unitary current. We found that the inhibitory effect on neuronal nAChRs is shared by all four dynorphins studied. The inhibition appears to be non-competitive and voltage independent. The outside-out recording together with other experiments indicated that a major part of this inhibition is not mediated through cytoplasmic messengers, but based on the direct action of dynorphins on neuronal nAChRs leading to the reduction of open time.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1460-9568.2000.00012.x
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  • 2
    Electronic Resource
    Electronic Resource
    Inhibition of the neuronal nicotinic receptor-mediated current by kappa opioid receptor agonists in PC12 cells (1998)
    Springer
    Pflügers Archiv 436 (1998), S. 887-893 
    Details
    ISSN: 1432-2013
    Keywords: Key words Dynorphins ; Kappa opioid receptor ; Nicotinic receptors ; Opioids ; Patch clamp ; PC12 cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The authors studied effects of opioid receptor agonists on neuronal nicotinic-receptor-mediated current in PC12 cells using whole-cell current recording. At 1 µM, [d-Ala, N-Me, Phe, Gly-ol]- enkephalin (DAMGO), a selective µ receptor agonist, or 10 µM methionine-enkephalin, a µ and δ receptor agonist, did not inhibit the current elicited by 30 µM nicotine significantly. Dynorphin A (1–17) (0.1–1 µM), an endogenous κ receptor agonist, and U50488 (0.1–10 µM), a non-peptide selective κ receptor agonist, depressed the nicotine-induced current reversibly in a dose-dependent manner. They accelerated the current decay, resulting in greater effects on the non-desensitized current than the peak current. These effects were not affected by nor-binaltrophimine, a selective κ receptor antagonist, or by inclusion of guanosine 5′-O-(2-thiobiphosphate) (GDP[β-S]), a GTP binding protein blocker, into the pipette solution. These results demonstrate that two κ opioid receptor agonists, dynorphin A (1–17) and U50488, inhibit neuronal nicotinic-receptor-mediated current without the involvement of opioid receptors or GTP binding proteins. The acceleration of the current decay suggests a direct action on nicotinic receptors such as open channel block, or augmentation of desensitization. Modulation of neuronal nicotinic receptors by dynorphins may play a role in some areas where dynorphin release sites and neuronal nicotinic receptors are colocalized.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004240050719
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  • 3
    Electronic Resource
    Electronic Resource
    Specialty polymeric membranes. V. Selective permeation of carbon dioxide through synthetic polymeric membranes having 2-(N,N-dimethyl)aminoethoxycarbonyl moiety (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 58 (1995), S. 1771-1778 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Permeation of CO2 was investigated by using synthetic polymeric membranes having a tertiary amine moiety, 2-(N,N-dimethyl)aminoethoxycarbonyl moiety. Permselectivity of the present membranes towards CO2 was achieved. Through poly{2-(N,N-dimethyl)aminoethyl methacrylate-co-acrylonitrile} (DMAEMA/AN-199) membrane, where DMAEMA mol fraction was 0.199, the separation factor towards CO2 for CO2/N2 separation ranged from 60 to 90, ranging in the CO2 partial pressure in the feed gas from 61 to 3.6 cmHg. © 1995 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1995.070581015
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  • 4
    Electronic Resource
    Electronic Resource
    Pressure dependence of gas permeability in a rubbery polymer (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 61 (1996), S. 945-950 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The effect of pressure on gas permeability of a rubbery polymer, 1,2-polybutadiene, is investigated for 15 gases with various molecular sizes and solubilities in the ranges of pressure up to 110 atm at 25°C. The permeability for slightly soluble gases (He, Ne, H2, N2, O2, and Ar) decreases with increasing pressure, and that for soluble gases (CH4, Kr, CO2, N2O, C2H4, Xe, C2H6, C3H6, and C3H8) increases with increasing pressure. Logarithms of permeability coefficient versus feed-gas pressure for the slightly soluble gases, CH4 and Kr, is linear within each pressure range, whereas such plots become convex toward the pressure axis for more soluble gases, such as CO2, N2O, C2H4, Xe, C2H6, C3H6, and C3H8. By analyzing the pressure dependence of permeability using sorption data of the gases, contributions of concentration and hydrostatic pressure to the gas diffusivity are estimated. © 1996 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Effect of penetrant-induced isothermal glass transition on sorption, dilation, and diffusion behavior of polybenzylmethacrylate/CO2 (1996)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 34 (1996), S. 2027-2033 
    Details
    ISSN: 0887-6266
    Keywords: Sorption ; dilation ; diffusion ; penetrant-induced isothermal glass transition ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effect of a penetrant-induced isothermal glass transition on sorption, dilation, and diffusion behavior was studied in a single experimental run for CO2 in cast polybenzylmethacrylate films. The dual-mode type sorption isotherms below the glass transition temperature of the polymer changed to linear ones above a certain concentration. Meanwhile, partial molar volume of CO2 determined from the dilation of the films above the concentration gave a value very close to the one reported for rubbery polymers, and diffusion coefficients became less concentration-dependent. The results were conformable to the concept of unrelaxed volume in glassy polymers. © 1996 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Thermodynamic interactions in rubbery polymer/gas systems (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 35 (1997), S. 1049-1053 
    Details
    ISSN: 0887-6266
    Keywords: thermodynamic interaction ; Flory-Huggins parameter ; rubbery polymer ; gas ; Henry's law coefficient ; partial molar volume ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Flory-Huggins interaction parameters χ for 23 gases (He, Ne, Ar, Kr, Xe, H2, N2, O2, N2O, CO2, CH4, C2H4, C2H6, C3H6, C3H8, 1,3-C4H6, four C4H8's, n-C4H10, iso-C4H10, and n-C5H12) in five rubbery polymers (1,2-polybutadiene (PB), poly(ethylene-co-vinyl acetate)) (EVAc), polyethylene (PE), polypropylene (PP), and poly(dimethyl siloxane) (PDMS) were determined from either literature data on Henry's law coefficient and partial molar volume or those on sorptive dilation for each polymer/gas system. Values of χ for the gases increased in the order of PDMS 〈 PP ≡ PB 〈 EVAc ≡ PE. Among the gases except He and H2 whose χ values are not reliable, Ne and Xe have respectively the highest and the lowest values of χ for the polyolefins. The χ values of the hydrocarbons were compared together with previously reported χ values of n-alkanes C3-C10. The dependencies of χ upon concentration and temperature were discussed on the basis of the literature data. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 1049-1053, 1997
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Sorption, diffusion, and partial molar volumes of C4 hydrocarbons in rubbery polymers (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 33 (1995), S. 1663-1671 
    Details
    ISSN: 0887-6266
    Keywords: sorption ; diffusion ; partial molar volume ; butanes ; butenes ; butylene ; butadiene ; 1,2-polybutadiene ; poly(ethylene-co-vinyl acetate) ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Sorption and dilation isotherms and diffusion coefficients for seven hydrocarbons (n-butane, isobutane, 1-butene, cis-2-butene, trans-2-butene, isobutylene, and 1,3-butadiene) in two rubbery polymers, 1,2-polybutadiene (PB) and poly(ethylene-co-vinyl acetate) (EVAc), were measured at 25°C. Dissolution parameters (Henry's law coefficient and Flory-Huggins interaction parameter), partial molar volumes, and diffusion coefficients were determined. PB exhibited greater affinity and lower diffusivity than EVAc to the C4 gases, although the gases showed nearly the same partial molar volumes in the two polymers. The diffusivity of such elongated molecules as trans-2-butene in both polymers was higher than that of bulky molecules with similar partial molar volume, such as cis-2-butene and isobutylene. Pressure-dependent permeabilities of PB and EVAc films to the hydrocarbons were predicted and discussed based on the dissolution parameters and the diffusivities. © 1995 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1995.090331112
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  • 8
    Electronic Resource
    Electronic Resource
    Effects of CO2 conditioning on sorption, dilation, and transport properties of polysulfone (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 36 (1998), S. 1695-1702 
    Details
    ISSN: 0887-6266
    Keywords: sorption ; dilation ; diffusion ; conditioning effect ; glassy polymer ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Sorption, dilation, and diffusion behaviors were studied for the system of polysulfone/CO2 with regard to the effects of CO2 conditioning, i.e., exposure to high-pressure CO2. Concurrent measurements of solubility, dilation, and diffusivity were performed for polysulfone films before and after the conditioning at 25 and 50 atm. While the solubility and dilation were enhanced by the conditioning, the diffusivity appeared to be depressed. Results were analyzed on the basis of the dual-mode sorption model, with the assumption that the Henry's law dissolution was not affected by the conditioning. Consistent description was achieved then by attributing the changes to increased amount of Langmuir adsorption. The conditioning effect on the diffusivity, which had not been reported before based on CO2 sorption kinetics, suggests that the permeability of glassy polymers would not always be enhanced by the conditioning, but may also be decreased. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 1695-1702, 1998
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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