Beta-adrenergic receptor regulation, through cyclic AMP, of nerve growth factor expression in rat cortical and cerebellar astrocytes.

1. Type 1 astrocytes prepared from 3-day rat cortex and cerebellum express the 1.3-kb nerve growth factor (NGF) mRNA and synthesize and release beta-NGF. 2. Isoproterenol (IP), a beta-adrenergic agonist, stimulates NGF mRNA content in cortical astrocytes; this increase is blocked by the beta-adrenergic antagonist propranolol but not the alpha-antagonist phenoxybenzamine. The EC50 for the effect of IP is 5 nM. 3. IP increases astrocyte cyclic AMP as does forskolin, which directly activates adenylate cyclase and also increases NGF mRNA content. Cerebellar astrocytes contain about one-third as much NGF mRNA, which can also be increased by forskolin and cyclic AMP. 4. These results suggest that CNS astrocytes can serve as a source of NGF and that the NGF gene is one of the class of cyclic AMP regulated genes.