Incorporation of ³H‐valine into soluble protein of cultivated astroglial cells after morphine treatment

Abstract

Uptake and incorporation of 3H-valine into soluble protein of cultivated astroglial cells from newborn rat cerebral hemispheres increased after incubating the cells for 4 hr in 10(-6) or 10(-5) M morphine. The effects, inhibited by high naloxone concentrations, were not mediated by cyclic adenosine monophosphate (cAMP)-activated binding sites for morphine or D-alanine2-methionine-enkephalin-amide (D-ala2-met-enk-amide). The cultures consisted of 60-70% astrogliallike cells. By changing the kinetics of labeling it was shown that morphine affects protein synthesis of the cells in a concentration- and time-dependent way. Even in the incubation medium increased amounts of labeled proteins were found in a time-dependent way after morphine administration in different doses. Gel electrophoresis in sodium-dodecyl sulphate (SDS) revealed that proteins with subunits in molecular weight (m.w.) regions of 40,000-50,000 were increased in the cells and in the medium after morphine (10(-6) or 10(-5) M) treatment. Labeled proteins with subunits of approximately 40,000 and approximately 70,000 in the cells and medium, respectively, were decreased after morphine treatment. By exploring the field of glial protein metabolism after morphine treatment, information could be obtained on the interactions between astroglia and neurons in opiate action and during tolerance development.

Exploring the Neuroimmunopharmacology of Opioids: An Integrative Review of Mechanisms of Central Immune Signaling and Their Implications for Opioid Analgesia

“…For example, Hansson and Rönnbä ck (1983) reported significant opioid effects on protein synthesis in astrocyte cultures in the absence of classic morphine binding sites. Rönnbä ck and Hansson (1985) and Hansson and Rönnbä ck (1985) continued this discussion of the role of astrocytes in the development of opioid tolerance, suggesting that the synthesis of proteins that is required for the development of tolerance and physical dependence are not related to the opioid receptor actions.…”

Effect of Antidepressants on ATP Content, ³H-Valine Incorporation and Cell Morphometry of Astrocytes Cultured from Rat Brain

“…The use of 3H-valine allows only the assessment of aminoacid incorpo ration into proteins. Hansson and Ronnback [33] have shown that 3H-valine incorporation into astrocyte protein is linear. In our experiments incorporation time was 3 h. Moreover, 3 uCi of 3H-valine added to each Petri dish were found to be the optimum.…”

“…The cells were incubated with 3 pCi/dish (4 ml) of L-[3. 4-'H]-valine (57.3 Ci/mmol) for 3 It in serum-free DMEM [33], The incubation was terminated by aspiration of the medium and astrocytes were rinsed twice with ice-cold Grey's balanced salt solution [34], Cells were scraped from the dishes with a plastic policemann (Costar. Co, Cambridge, Mass.)…”