Amino acid incorporation during morphine intoxication Electrophoretic separation of extracellular proteins from a brain stem astroglial and neuronal containing co-cultivation system.

Extracellular proteins from brain stem astroglial enriched primary cultures were resolved with gel electrophoresis after labelling the cultures with (3)H/(14)C (experimental/control) valine. A protein fraction with a subunit molecular weight (mol. wt) of approx. 40,000 increased in (3)H/(14)C valine labelling after incubating the cultures for 1 h in 10(?6) or 10(?5) M morphine or after incubation for 4 h in 10(?7)M morphine. After incubating the cultures for up to 4 h in 10(?6) or 10(?5)M morphine proteins with subunits of mol. wt: ?15,000, 40,000 and 80,000 increased in labelling while subunits with mol. wt: ?65,000 and 100,000 decreased in labelling. After co-cultivating the astroglial-enriched primary brain stem cultures for 1 week with fetal (neuronal containing) brain stem cultures, incubation in 10(?) or 10(?6)M morphine for 1 h increased extracellular (3)H/(14)C labelling of electrophoretically resolved material with mol. wt ?15,000 and 40,000. After incubation in the same concentrations for 2 h an additional 80,000 mol. wt fraction increased in (3)H/(14)C labelling. After incubation in 10(?6)M morphine for 4 h the same result as above was obtained, the changes in the 15,000 and 80,000 mol. wt fractions being blocked by prior addition of 10(?6)M naloxone hydrochloride. Incubation in 10(?5)M morphine did not result in significant changes in the co-cultivation system used. It is suggested that extracellular proteins, mainly astroglial-derived, might serve functions during morphine intoxication. Co-cultivation of astroglial-enriched and neuronal containing cultures might be one model system to study macromolecular communication between these cell types.