Modulation of adenosine agonist [3H]N6-(R)-phenylisopropyladenosine binding to pig brain cortical membranes by changes of membrane fluidity and of medium physicochemical characteristics.

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  • Additional Information
    • Source:
      Publisher: Elsevier Science Country of Publication: Netherlands NLM ID: 1254354 Publication Model: Print Cited Medium: Print ISSN: 0014-2999 (Print) Linking ISSN: 00142999 NLM ISO Abbreviation: Eur J Pharmacol Subsets: MEDLINE
    • Publication Information:
      Publication: 2005- : Amsterdam : Elsevier Science
      Original Publication: Amsterdam, North Holland Pub. Co.
    • Subject Terms:
      Membrane Fluidity*; Cerebral Cortex/*metabolism ; Phenylisopropyladenosine/*metabolism; Animals ; Cell Membrane/metabolism ; In Vitro Techniques ; Sucrose/pharmacology ; Swine
    • Abstract:
      The binding of [3H]N6-(R)-phenylisopropyladenosine ([3H]R-PIA) to pig brain cortical membranes was investigated as a function of membrane fluidity and of the physicochemical characteristics of the medium. The two affinity states of the A1 adenosine receptor behave differently in the experiments performed. Increases (up to 6.7 poises) or reduction (up to 1.3 poises) in membrane microviscosity did not lead to significant variation of equilibrium parameter values except for a slight modification of the low-affinity Kd value at 1.3 poises. Addition of cholesterol to raise the microviscosity up to 9.0 poises led to a marked decrease of binding to the high-affinity state without modifying the Kd. Furthermore, the Kd value for the low-affinity state rose markedly. Addition of sucrose, which modifies the conductance, viscosity and density of the aqueous medium, did not lead to significant changes when used at a concentration of 0.25 M, either in isolation or in radioligand binding assay medium. The presence of 0.32 M sucrose in the isolation medium led to a 30% fall in the total binding without affecting the distribution and Kd values for either affinity state very much. However, the presence of greater than or equal to 0.32 M sucrose in the binding assay medium produced the disappearance of the low-affinity states and the appearance of high-affinity states; only one affinity state was found to have a somewhat increased Kd value. On the other hand, increases of the medium conductance did not lead to the disappearance of the low-affinity state although some decrease of the binding was observed at high Tris concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)
    • Accession Number:
      29193-86-0 (Phenylisopropyladenosine)
      57-50-1 (Sucrose)
    • Publication Date:
      Date Created: 19920114 Date Completed: 19920408 Latest Revision: 20190624
    • Publication Date:
      20250114
    • Accession Number:
      10.1016/0922-4106(92)90032-q
    • Accession Number:
      1541326