Respiration in rat cerebral astrocytes from primary culture

Respiration was measured polarographically in astrocytes from dissociated neonatal rat cerebra grown in primary culture. Cells grown in a modified Eagle's minimal essential medium containing 20% fetal calf serum for 14 to 21 days respired at a rate of 34.23 n at. equiv 0 mg protein-1 min-1. Cells which were grown in this medium for 14 days and the grown in serum-free medium containing 0.25 mM dibutyrylcyclic-AMP (dbcAMP) for three to six days, had respiratory rates 20% higher than in cells from untreated control cultures (P = 0.005). Maximal inhibition by oligomycin required 200 pmole per mg protein for dbcAMP-treated cells and 80 pmole per mg protein for untreated cells. Oligomycin inhibited the respiration of both dbcAMP-treated and untreated cells by about 70%. At a concentration of 175 nmole per mg protein, 2,4-dinitrophenol (DNP) produced a maximal stimulation of respiration, which was 191% of the resting rate in dbcAMP-treated cells and 218% of the resting rate in untreated cells. The maximal DNP-stimulated respiratory rates were the same in dbcAMP-treated and untreated cells.