Evidence for a high-affinity uptake system for cholecystokinin octapeptide (CCK8) in rat cortical synaptosomes.

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  • Author(s): Migaud M;Migaud M; Roques BP; Durieux C
  • Source:
    The European journal of neuroscience [Eur J Neurosci] 1995 May 01; Vol. 7 (5), pp. 1074-9.
  • Publication Type:
    Journal Article
  • Language:
    English
  • Additional Information
    • Source:
      Publisher: Wiley-Blackwell Country of Publication: France NLM ID: 8918110 Publication Model: Print Cited Medium: Print ISSN: 0953-816X (Print) Linking ISSN: 0953816X NLM ISO Abbreviation: Eur J Neurosci Subsets: MEDLINE
    • Publication Information:
      Publication: : Oxford : Wiley-Blackwell
      Original Publication: Oxford, UK : Published on behalf of the European Neuroscience Association by Oxford University Press, c1989-
    • Subject Terms:
      Cerebral Cortex/*metabolism ; Sincalide/*metabolism ; Synaptosomes/*metabolism; Animals ; Carbonyl Cyanide m-Chlorophenyl Hydrazone/pharmacology ; Cerebral Cortex/drug effects ; Dose-Response Relationship, Drug ; Male ; Ouabain/pharmacology ; Rats ; Rats, Sprague-Dawley ; Sincalide/pharmacology ; Sucrose/pharmacology ; Synaptosomes/drug effects ; Temperature ; Time Factors
    • Abstract:
      Given the high resistance of the cholecystokinin octapeptide (CCK8) to in vivo peptidase degradation, the possible existence of a reuptake system for this peptide was investigated. Efficient accumulation of intact, tritiated propionyl CCK8 ([3H]pCCK8) was observed following its incubation with rat cortical synaptosomes but not with cerebellar synaptosomes, where no cholecystokinin immunoreactivity was found. This uptake process appeared to be dependent on temperature, duration of incubation, concentration of radioligand, the presence of glucose and the integrity of the synaptosomes. A Lineweaver-Burk analysis indicated that the putative uptake process is characterized by a single Km value of 10.7 nM and a Vmax of 8.5 fmol/min/mg of protein. Carbonyl cyanide-m-chlorophenyl hydrazone, an uncoupler of oxidative phosphorylation, blocked accumulation of [3H]pCCK8, whereas ouabain did not. The uptake was found to be highly specific since, among all the cholecystokinin analogues tested, only CCK8 and, to a lesser extent, CCK7, were able to inhibit [3H]pCCK8 uptake. The rate of [3H]pCCK8 uptake was not affected by CCK4, CCK5, D-Trp CCK8, BC 264, a potent and radioactivity was observed using [3H]pBC 264, a result which is not in favour of a cholecystokinin receptor-induced internalization mechanism. The potent and selective uptake mechanism characterized in this study could participate, in conjunction with extra and intracellular degradation of CCK8 by peptidases, in the interruption of cholecystokinin-conveyed messages in the brain.
    • Accession Number:
      555-60-2 (Carbonyl Cyanide m-Chlorophenyl Hydrazone)
      57-50-1 (Sucrose)
      5ACL011P69 (Ouabain)
      M03GIQ7Z6P (Sincalide)
    • Publication Date:
      Date Created: 19950501 Date Completed: 19950823 Latest Revision: 20190815
    • Publication Date:
      20221213
    • Accession Number:
      10.1111/j.1460-9568.1995.tb01094.x
    • Accession Number:
      7613612