Z1046: biochemical characterization of its dopaminergic activity.

Affinity of Z1046 for dopamine receptor subtypes, its ability to modulate D1- and D5-mediated AC stimulation and D1-induced cAMP accumulation were evaluated. On D1-like receptors Z1046 and fenoldopam (fen) showed a similar high affinity, being more potent than DP-5,6-ADTN and 5,6-ADTN. For the D2-like receptors, the affinity rank orders were: D2: Z1046 > or = DP-5,6-ADTN > fen = 5,6-ADTN; D3: Z1046 > DP-5,6-ADTN > fen = 5,6-ADTN; D4: Z1046 = DP-5,6-ADTN > fen = 5,6-ADTN. In AC studies the rank order was: Z1046 = fen > DP-5,6-ADTN > 5,6-ADTN. Z1046 was more efficient than fen in stimulating cAMP accumulation. These results make Z1046 an innovative agent combining D1-like and D2-like activities.