Molecular cloning and characterization of crustacean type-one dopamine receptors: D1αPan and D1βPan

Dopamine (DA) differentially modulates identified neurons in the crustacean stomatogastric nervous system (STNS). While the electrophysiological actions of DA have been well characterized, little is known about the dopaminergic transduction cascades operating in this system. As a first step toward illuminating the molecular underpinnings of dopaminergic signal transduction in the crustacean STNS, we have cloned and characterized two type-one DA receptors (DARs) from the spiny lobster (Panulirus interruptus): D1αPan and D1βPan. We found that the structure and function of these arthropod DARs are well conserved across species. Using a heterologous expression system, we determined that DA, but not serotonin, octopamine, tyramine or histamine activates these receptors. When stably expressed in HEK cells, the D1αPan receptor couples with Gs, and DA elicits an increase in [cAMP]. The D1βPan receptor responds to DA with a net increase in [cAMP] that is mediated by Gs and Gz.