The changes stress generation in the umbilical vein segments were assessed by wire myography in response to 109 mM K+ depolarization (A and B) and 1 μM thromboxane agonist (U46619, B and D) 24 hours post- exposure to intratracheal instillation (IT) of 100 μg /kg of (S)-MWCNTs or 10% surfactant (A and C) or intravenous administration (IV) of (D)-MWCNTs or DPPC/RSA (B and D), from 17 - 19 days pregnant Sprague Dawley rats (n = 12). The percentage relaxation in response to sodium nitroprusside (SNP) following U46619 (1 μM) pre-contraction in the umbilical vein 24 hours post- exposure to intratracheal instillation of (S)- MWCNTs or 10% surfactant (E) or intravenous administration of (D)-MWCNT or DPPC/RSA is graphed (F) (n = 12).
