AIM: To define the role of dopamine-2 receptors in the sympatho-inhibitory effects of Y-l-glutamyl-l-dopa in conscious rabbits. METHOD: γ-l-glutamyl-l- dopa ( gludopa ) was infused iv at 25 and 100ug#·kg-1. min-1 with and without prior dopamine-2 receptor blockade by YM-09151-2 (50 ng·kg~1 iv) in conscious rabbits. RESULTS: Mean arterial pressure and heart rate remained unchanged while renal plasma flow increased. Arterial norepinephrine (NE) concentration, total and renal NE spillover rate were markedly decreased in a dose-related manner, which were not affected by prior dopamine-2 receptor blockade . Gludopa was detected in the whole brain (92+112 ng/g wet brain tissue) at the end of experiment although brain tissue lev-odopa, NE, and dopamine contents were not much different from those in the control group. CONCLUSION: Gludopa decreased dose-dependently plasma NE concentration, and total and renal NE overflow to plasma, which were not mediated by activation of dopamine D2 receptors. AIM: To define the role of dopamine-2 receptors in the sympatho-inhibitory effects of Yl-glutamyl-l-dopa in conscious rabbits. METHOD: γ-1-glutamyl-l-dopa (gludopa) was infused iv at 25 and 100 ug # · Kg -1 · min-1 with and without prior dopamine-2 receptor blockade by YM-09151-2 (50 ng · kg -1 iv) in conscious rabbits. RESULTS: Mean arterial pressure and heart rate remained unchanged while renal plasma flow increased. Arterial norepinephrine (NE) concentration, total and renal NE spillover rate were markedly decreased in a dose-related manner, which were not affected by prior dopamine-2 receptor blockade. Gludopa was detected in the whole brain (92 + 112 ng / g wet brain tissue) at the end of experiment although brain tissue lev-odopa, NE, and dopamine contents were not much different from those in the control group. CONCLUSION: Gludopa decreased dose-dependently plasma NE concentration, and total and renal NE overflow to plasma, which were not mediated by activation of dopamine D2 recepto rs.