The changes in the contractile responses were assessed by wire myography of the thoracic aorta from 17 - 19 days pregnant (A, C and E) and non-pregnant female (B, D and F) Sprague Dawley rats, 24 hours following intratracheal instillation of 100 μg/kg of (S)-MWCNTs or 10% surfactant. The stress generation in response to cumulative concentrations of phenylephrine (PE; A and B) and endothelin 1 (ET-1; C and D) are plotted. The percentage relaxation form a 10 μM phenylephrine prestimulation stress level in response to cumulative concentrations of acetylcholine (Ach; E and F) is graphed. * indicates p < 0.05 compared to 10% surfactant while # indicates p < 0.05 compared to naïve using repeated measures ANOVA (n = 4 - 8). The p values were derived following the comparison of each concentration response curve across treatment groups using a regression analysis by examining the best-fit values.
