Primary cultures from defined brain areas; effects of seeding time on the development of beta-adrenergic- and dopamine-stimulated cAMP-activity during cultivation.

The influence of seeding time on the expression of beta-adrenergic- and dopamine-stimulated cAMP activity was studied in primary astroglial cultures from various brain areas. In all cultures isoproterenol (10(-7)-10(-5) M) caused an increased cAMP accumulation with time in culture. In brainstem cultures from 17-day-old embryos there was a decreased intracellular cAMP accumulation between 3 and 4 weeks. In all newborn rats and in striatal cultures from 7-day-postnatal rats there was a similar decrease between 2 and 3 weeks. These changes are discussed and interpreted as a differentiation of the cells concerning beta-receptors. The most prominent cAMP accumulation caused by isoproterenol was found in striatal cultures from newborn rat. Although isoproterenol and noradrenaline both caused intracellular cAMP accumulation, isoproterenol was the most effective. There was a cAMP accumulation specific to dopamine (10(-6)-10(-4)M) in 2-week-old striatal cultures from newborn rat, although there was an interaction with beta-adrenergic receptors. In the other cultures studied there was only a very small dopamine stimulation of cAMP. The expression of this heterogeneity among astroglial primary cultures from various brain areas seems to be influenced by the genetic program for cellular maturation and by specific cellular contacts in vivo until seeding and in culture.