Cell-to-cell adhesion of dissociated embryonic brain cells; the effects of metabolic inhibitors and temperature.

Brain cells from 16 to 18-day-old mice embryos were dissociated by mild trypsinization and rotated for 120 min. The area and density of of the adhesive complexes formed were registered using the method described previously. The adhesiveness of dissociated embryonic brain cells (measured during the 120 min of rotation) was diminished in the presence of inhibitors of protein synthesis (puromycin, cycloheximide and inhibition of mRNA synthesis actinomycin D). The inhibition was, however, not distinct, because 1 microgram/ml of cycloheximide and actinomycin was without any significant effect, and the degree of inhibition evoked by 10 micrograms/ml and 25 micrograms/ml of puromycin bordered on significance. However, protein synthesis inhibitors in long-term aggregation experiments had a pronounced inhibitory effect and/or induced destruction of the aggregates. Metabolic inhibitors (KCN and NaN3) caused an inhibition at the lowest level of significance (p less than 0.05) 10(-3) mol/l KCN reduced the final adhesive product significantly. Cells rotated at room temperature and at +5 degrees C adhere to the same extent as in control experiments (37 degrees C). The adhesion was significantly inhibited at +60 degrees C and also after freezing at -80 degrees C with subsequent thawing. The adhesion of cells exposed for 30 min to between +80 degrees C and 100 degrees C was completely abolished. The process of embryonic brain cell adhesion requires a low energy supply, and is relatively independent of biosynthetic processes and of temperature changes between +5 degrees C and +50 degrees C.