NEUROTRANSMITTERS ACTIVATE THE HUMAN ESTROGEN-RECEPTOR IN A NEUROBLASTOMA CELL-LINE

The human neuroblastoma cell line SK-N-SH has been used as a model sys tem to study the interactions of the human estrogen receptor (hER) wit h neurotransmitters. We have successfully transfected these cells usin g an adenoviral delivery system and have reconstituted ligand-dependen t responses to estradiol and ligand-independent responses to a series of dopamine D1 receptor agonists. The full. agonist for the D1 recepto r, SKF 82958, shows a robust activation of hER, comparable to that ind uced by estradiol. This activation is blocked by the protein kinase A inhibitor H-89, is mimicked by forskolin, and is therefore thought to be mediated in part through the cAMP/protein kinase A pathway. We have examined deletion mutants of hER for activation by SKF 82958 and find that both its transactivation domains, AF-1 and AF-2, must cooperate to impart the full response to the agonist. Significantly, an agonist of the muscarinic acetylcholine receptor, carbachol, though not active by itself, synergistically activates hER in conjunction with suboptim al doses of SKF 82958. This is the first reported instance of two neur otransmitters synergizing to activate a member of the nuclear receptor superfamily, and might predict a role for multiple neural inputs modu lating the effects of these receptors in the central nervous system. ( C) 1997 Elsevier Science Ltd.