Sumanirole maleate is a highly selective D2 receptor full agonist with an ED50 of about 46 nM.

Sumanirole maleate is a dopamine receptor agonist with greater than 200-fold selectivity for the D2 receptor subtype (Ki = 9 nM) versus the other dopamine receptor subtypes.In cell-based activity assays sumanirole demonstrates dopamine D2 receptor agonist activity with EC50 values between 17 and 75 nM.In vivo, sumanirole is a full agonist for elevation of striatal acetylcholine levels (ED50 = 12.1 μmol/kg i.p.) and suppresses dopamine neuron firing rates in the substantia nigra pars compacta (ED50 = 2.3 μmol/kg i.v.).Because of its efficacious activity in animal models of dopamine hypofunction, sumanirole may have therapeutic utility in Parkinson's disease.