Fig. 8.
Effects of frack sand dust (FSD) 8 on cardiac work (A, D and G), cardiac output (B, E and H) and stroke volume (C, F and I) responses to dobutamine in rats exposed to air or 30 mg/m3 FSD 8 (n = 6–8 air or FSD 8 rats per time point). One d after exposure to FSD 8, responsiveness to dobutamine was reduced (A–C). Seven d after exposure to FSD 8, dobutamine-induced increases in cardiac work were lower in exposed than in air-treated rats. Twenty-seven d following exposure to FSD 8, cardiac output and stroke volume returned to control levels (G-I). *P < 0.05.