Amino acid incorporation during morphine intoxication. II: Electrophoretic separation of extracellular proteins from cerebral hemisphere slices and astroglia-enriched primary cultures

✍ Scribed by E. Hansson; Dr. L. Rönnbäck

• Book ID: 102910624
• Publisher: John Wiley and Sons
• Year: 1985
• Tongue: English
• Weight: 648 KB
• Volume: 14
• Category: Article
• ISSN: 0360-4012
• DOI: 10.1002/jnr.490140409

✦ Synopsis

Radioactively labeled proteins were identified in a broad molecular weight range in the incubation medium of rat cerebral hernisphcre slice preparations or primary cultures after incubation with radioactive valine. Morphine chloride caused an increase in labeled niedia proteins with MW -40,000 and 65,000 in both preparations, whereas a fraction with MW, -80,000 decreased in amount. In the culture preparation a MW -15,000 fraction also decreased after morphine treatment. The effects on the MW 40,000 and 65,000 fractions by morphine could not be blocked by naloxone hydrochloride, an opiate antagonist. Labeled media proteins from primary cultures obtained from various brain regions showed many similarities. After l0W5 or 10W6 M morphine, protein fractions with MW -15,000, 25,000, 40,000, 65,000-70,000, 80,000, and 100,000 changed with increases or decreases in the various morphine concentrations. The 3H-labeling of the MW -40,000 fraction increased in all cultures, where it decreased.

In conclusion, proteins synthesized within cells in brain slices or in astrogliaenriched cultures are released or secreted into the incubation media. Some protein fractions are affected in different directions by morphine. The effects were not correlated with the presence of classical opiate receptors on the cells. This was so even though more changes in media proteins occurred in astroglial cultures from opiate receptor-rich brain regions than in similar cultures from opiate receptorpoor regions. The possible significance of proteins synthesizcd in astroglial cells and released extracellulary in opiate action is discussed.