Figure 5. Histograms depicting the effects of sodium nitroprusside (SNP), halothane, and isoflurane on total arterial compliance (C) (top), total arterial resistance (R) (middle), and characteristic aortic impedance (Z^c) (bottom). The low, medium, and high doses of volatile anesthetics were 1.25, 1.5, and 1.75 MAC, respectively. SNP doses were chosen to create comparable changes in mean arterial pressure (dose range 0.25-3 micro gram *symbol* kg sup -1 *symbol* min sup -1). *Significantly different (P < 0.05) from control; (dagger)significantly different (P < 0.05) from the low dose; (section)significantly different (P < 0.05) from value with the medium dose; (double dagger)significantly different (P < 0.05) from value with halothane at the same dose.