Figure 5. Effect of isoflurane on the prostacyclin-mediated component (stippled area, A and B), and the nitric oxide-mediated component (lined areas, C and D) of A23187-induced vasorelaxation in canine pulmonary arteries at low agonist concentrations. Relaxations were measured in arteries contracted to the ED50level of tension with phenylephrine and are expressed as percentages of phenylephrine contraction (n = 5). Although isoflurane attenuated (P < 0.05) the overall vasorelaxation response to A23187, it had no effect on the individual components of vasorelaxation mediated by either prostacyclin or nitric oxide.