Inhibition of dopamine synthesis by dopamine D2 and D3 but not D4 receptors.

摘要: The goal of the current study was to determine which D2-like receptors (D2, D3 or D4) are involved in autoreceptor regulation dopamine synthesis. We have derived a model system utilizing mouse mesencephalic cell line, MN9D, both synthesizes and releases dopamine, characterize modulation tyrosine hydroxylase activity, rate limiting enzyme conversion by receptors. Previously, we shown that stimulation D2 D3, but not D4, transfected into MN9D cells inhibited release dopamine. In study, show quinpirole K+-stimulated activity pertussis toxin-sensitive manner, strongly suggesting G-protein coupling as mechanistic pathway. receptor effect could be maintained for at least 60 min, whereas desensitized. Treatment with 10 microM forskolin, raises cyclic AMP levels 100 nM okadaic acid, potent phosphatase inhibitor, had no on D2-or D3-mediated inhibition, these effects may independent AMP- acid-sensitive activity. Taken together, data confirm hypothesis can perform dual roles regulation.