RU38486 blocks the steroid regulation of transmitter choice in cultured rat sympathetic ganglia.

Sympathetic neurones grown in tissue culture change phenotype from adrenergic to cholinergic due to a factor released by non-neuronal cells. Glucocorticosteroids prevent the production of this factor by non-neuronal cells and hence prevent the change in phenotype. Conventional steroid antagonists, however, fail to block this effect. We report here that the steroid antagonist RU38486 is effective in preventing the action of corticosterone on cultured sympathetic ganglia and hence may be a useful in vivo tool to study the steroid regulation of development.