The regulation of δ-opiate receptor density on 108CC15 neuroblastoma × glioma hybrid cells

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Abstract

  • 1The effect of exogenous substances on the expression of opiate receptors on 108CC15 neuroblastoma × glioma hybrid cells has been studied.
  • 2Cell differentiation by culture in the presence of N6-O2-dibutyryl adenosine 3′,5′-cyclic monophosphate induced a three fold increase in opiate receptor density.
  • 3When the cells were grown in the presence of 10−5 m morphine hydrochloride for up to 23 days, opiate receptor densities were reduced by only 30% when compared with matched controls.
  • 4Culture in the presence of 10−7md-Ala2-d-Leu5-enkephalin produced opiate receptor down regulation of 73% compared to controls after only 4 h of treatment.
  • 5The down regulation process could be inhibited by continued exposure to d-Ala2 d-Leu5-enkephalin at concentrations greater than 4 nm; below this concentration down regulation was rapid and irreversible.
  • 6A model to explain these observations is described.

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