DRD2 and cerebrovascular disorder: Interestingly, MZD, A, B and C demonstrated higher potency than three clinically available agents shown to inhibit PMA-stimulated O2- generation: propentofylline, a selective phosphodiesterase inhibitor (IC50 >100 μM) [60], cabergoline, a potent and selective agonist of D2-dopamine receptors (IC50 >100 μM) [59], and nicergoline, an ergoline derivative used for cerebrovascular diseases (IC50 = 10–15 μM) [58].