Intracellular cAMP increased 9-fold in cerebral hemisphere primary cultures after incubation with dopamine (10(-4) M). The effect was dose- and time-dependent (10(-6) M-10(-4) M; 2-10 minutes). It was mimicked, to some extent, by the partial agonist apomorphine (10(-5) M-10(-4) M) and antagonized by fluphenazine (10(-5) M-10(-4) M). The elevation of cAMP caused by dopamine was incompletely antagonized by propanolol (10(-5) M-10(-4) M), obviating an interaction with beta-adrenergic receptors. A beta-adrenergic effect was antagonized by propranolol but only slightly by fluphenazine. The effect of dopamine on cAMP-level was more pronounced in a subpopulation of the hemisphere culture, i.e. in astroglial cultures from the striatum, 12-fold compared with controls at 10(-4) M. No dopamine stimulated formation of cAMP was found in primary cultures from brain-stem. The results demonstrated some heterogeneity among astroglial cells. The cultures used contained mainly astroglial-like cells, as judged from immunohistochemical localization of the glial specific proteins S 100 and GFA (alpha-albumin). No mature neurons or oligodendroglial cells have so far been demonstrated in the cultures.