Figure 2. Changes in cardiac output (top) and total peripheral resistance (bottom) in response to 10 mg/kg N^W-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide synthesis, in conscious and inactin- and halothane-anesthetized rats. Values represent the mean plus/minus 1 SE for each experimental group; conscious (n = 8), inactin-anesthetized (n = 8), and halothane-anesthetized rats (n = 8). *Significant change in response to L-NAME (P < 0.05); a = change induced by L-NAME is significantly different from conscious rats (P < 0.05); b = change induced by L-NAME is significantly different from inactin-anesthetized rats (P < 0.05).