Macromolecular changes in brain stem of morphinized rats
Incorporation of [3H]valine into trichloroacetic acid-(TCA)-precipitable, water-soluble or membrane-bound material of whole brain and brain-stem did not differ significantly in morphine-intoxicated, morphine abstinent and control rats. The animals were intoxicated with morphine (final dose 340 mg/kg b.w.) for 15 days, using an ingestion method with no impairment of the caloric intake compared to controls. Abstinent rats were withdrawn from morphine for 2 days after 13 days of intoxication. Measurements of [3H]valine or [14C]valine incorporated into soluble or membrane-bound brain stem proteins failed to demonstrate any significant changes in specific protein bands from morphinized rats. Separation was achieved by polyacrylamide gel electrophoresis with or without sodium-dodecyl sulphate (SDS) or by isoelectric focusing. After immunoabsorption chromatography to remove those proteins antigenically similar to serum proteins, an increase in the staining intensity and in incorporation of [3H]valine into two protein bands (with isoelectric points (Ip:s) 5.75 and 7.7) was seen in brain stem from long-term morphine-intoxicated rats. The results show that macromolecular interactions are involved in long-term morphine actions.
KeywordsMorphine Valine Protein Band Brain Stem Isoelectric Point
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- 7.Goodman, R. R., Snyder, S. H., Kuhar, M. J., andYoung III, W. S. 1980. Differentiation of delta and mu opiate receptor localizations by light microscopic autoradiography. Proc. Natl. Acad. Sci. (USA) 77:6239–6243.Google Scholar
- 12.Lee, N. M., Craves, F. B., andStokes, K. B. 1979. Effect of opiates on macromolecular biosynthesis, pages 521–539,in Loh, H. H. andRoss, D. H. (eds.) Neurochemical mechanisms of Opiates and Endorphins (Adv. Biochem. Psychopharmacol. Vol. 20), Raven Press, New York.Google Scholar
- 16.Mans, R. J., andNovelli, G. D. 1968. Measurement of the incorporation of radioactive amino acids into protein by a filter-paper disc method. Arch. Biochem. Biophys. 94:48–53.Google Scholar
- 25.Vesterberg, O. 1973. Isoelectric focusing of proteins in thin-layers of polyacrylamide gel. Sci. Tools 20:22–29.Google Scholar