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  • Electronic Resource  (4)
  • 1980-1984  (4)
  • Clonidine  (2)
  • Polymer and Materials Science  (2)
  • General Chemistry
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 314 (1980), S. 83-87 
    ISSN: 1432-1912
    Keywords: Guinea-pig ileum ; Presynaptic α-adrenoceptors ; Clonidine ; Morphine ; α-Adrenoceptor blocking agents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The purpose of the present study was to further characterize the α-adrenoceptors located on parasympathetic fibres. Segments of guinea-pig ileum were stimulated by transmural electrical pulses, and the ensuing contractions, which are due to the release of acetylcholine from postganglionic parasympathetic fibres, were monitored. Clonidine and tramazoline, which are thought to act preferentially on presynaptic α-adrenoceptors, reduced the contractions, whereas phenylephrine and methoxamine, postsynaptic α-adrenoceptor agonists, were ineffective. Contractions induced by acetylcholine were not changed by clonidine but were abolished by atropine. Yohimbine, piperoxan, phentolamine and thymoxamine reversed or prevented the inhibitory effect of clonidine. Prazosin and AR-C239 did not antagonize this effect. The inhibitory effect of tramazoline was antagonized by piperoxan but not by AR-C239 or by prazosin. Naloxone did not alter the action of clonidine, and piperoxan did not change the inhibitory effect of morphine. In conclusion, these experiments suggest the presence on cholinergic postganglionic fibres of both opiate receptors and α-adrenoceptors. The latter appear to resemble more closely α1-adrenoceptors than α1-adrenoceptors.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 318 (1982), S. 288-294 
    ISSN: 1432-1912
    Keywords: Mianserin ; Clonidine ; Desipramine ; Acetylcholine ; α2-Adrenoceptors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The purpose of the present study was to characterize the effects of mianserin at α2-adrenoceptors. Firstly, the action of mianserin on postganglionic sympathetic fibres has been studied using the tachycardia induced by stimulation of the cardiac nerve in dogs. Mianserin increased this tachycardia, but could not prevent the inhibitory effect of clonidine in this model. However, an antagonistic effect of mianserin against clonidine was observed when animals were pretreated with desipramine. Secondly, mianserin antagonized the inhibitory effect of clonidine on the electrically stimulated guinea-pig ileum. In high concentrations, mianserin reduced both electrically and acetylcholine induced contractions. Thirdly, mianserin antagonised the sleep induced by clonidine in chickens. These results are consistent with α2-adrenoceptor blocking properties of mianserin in peripheral noradrenergic fibres in dogs, in cholinergic fibres in guinea-pig ileum and in the central nervous system in chickens.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 22 (1983), S. 241-246 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 13C-, 1H-nmr, CD, and x-ray crystallography revealed β-turns of type III for Boc-Gly-L-Ala-Aib-OMe, Boc-L-Ala-Aib-L-Ala-OMe; the 310-helix for Boc-Aib-L-Ala-Aib-L-Ala-Aib-OMe; and antiparallel arranged α-helices for Boc-L-Ala-Aib-Ala-Aib-Ala-Glu(OBzl)-Ala-Aib-Ala-Aib-Ala-OMe. An N-terminal rigid α-helical segment is found in the polypeptide antibiotics alamethicin, suzukacillin, and trichotoxin. The α-helix dipole is essential for their voltage-dependent pore formation in lipid bilayer membranes, which is explained by a flip-flop gating mechanism based on dipole-dipole interactions of parallel and antiparallel arranged α-helices within oligomeric structures.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Propellants, Explosives, Pyrotechnics 9 (1984), S. 193-200 
    ISSN: 0721-3115
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The use of modified forms of the Rosenthal electrothermal equation to aid in the design of a capacitor discharge firing circuit for a specific detonator is described. The electrothermal parameters Cp and γ, representing the heat capacity of the bridge and the heat loss factor, respectively, were calculated from previously obtained firing data for the detonator. These calculations provided input to the design of a firing circuit utilizing electrolytic capacitors, which have a large value of electrical capacity but also a non-negligible internal resistance. Calculations were performed which (1) revealed the degrading effect on detonator initiation caused by too large a value of internal resistance, and (2) permitted selection of a particular capacitor that would allow reliable functioning of the detonator with initiation times of about 230 μs. The circuit was designed utilizing this capacitor, and in the experimental evaluation of the circuit the measured initiation times were compared with the calculated values. Good agreement between the two was documented, and the conclusion was reached that the detonator functioned reliably. The merits of the electrothermal analysis and the assumptions utilized therein relative to a vigorous heat transfer/reaction kinetics modeling of the flow of energy from the bridge into the explosive flash charge are discussed in detail.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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