Effects of vehicle, NCX 4016, aspirin, L-arginine and D-arginine on perfusion pressure of perfused rat tail arteries during 14 min-treatment with NG-monomethyl-L-arginine (L-NMMA). Drugs were given through the arteries for 15 min before L-NMMA and this treatment was maintained until the end of L-NMMA administration. Values are means±s.e.mean, n=7 different arteries per group. Considering the area under the curves: P<0.05 for NCX 4016 (25 μM), P<0.01 for NCX 4016 (50 μM), P<0.001 for NCX 4016 (100 μM) and L-arginine (100 μM) all compared to vehicle-treated preparations.