Nepicastat (3-100 mg/kg; p.o.; three consecutive times, 12 hours apart times) produces dose-dependent decreases in noradrenaline content, increases in dopamine content and increases in dopamine/noradrenaline ratio in the artery (mesenteric or renal), left ventricle [3]. Animal Model: 15-16 weeks male spontaneously hypertensive rats (SHRs) [3] Dosage: Oral administration; three consecutive times, 12 hours apart Administration: 3, 10, 30, 100 mg/kg Result: Produced dose-dependent decreases in noradrenaline content, increases in dopamine content and increases in dopamine/noradrenaline ratio in the artery (mesenteric or renal), left ventricle and cerebral cortex.