Figure 4. The effect of 1, 10, and 30 mg/kg N^G-L-arginine methyl ester (L-NAME) and N^G-monomethyl L-arginine (L-NMMA); 20, 80, and 400 mg/kg 7-nitro-indazole (7-NI); or 1.6%, 1.8%, and 2% increasing isoflurane concentrations on minute ventilation (V with dot^E) at 8%, 9%, and 10% end-tidal carbon dioxide (ETCO²). * L-NAME and L-NMMA (10 and 30 mg/kg) and isoflurane (1.8% and 2%) significantly (P <0.05) decreased V with dot^Eat 8%, 9%, and 10% ETCO²compared with time controls. Data are means +/- SD.