ET A receptors are the primary mediators of myofilament calcium sensitization induced by ET‐1 in rat pulmonary artery smooth muscle: a tyrosine kinase independent pathway

Rat pulmonary artery smooth muscle (arterial rings permeabilized using alpha-toxin in the presence of A23187 and pre-constricted with pCa 6.8)

ET-1 (1 microM) with or without ETA receptor antagonist BQ 123 (100 microM), ETB receptor antagonist BQ 788 (100 microM), or tyrosine kinase inhibitor Tyrphostin A23 (100 microM)

Control conditions (absence of antagonists or presence of pCa 6.8 alone)

Constriction force (mN) and level of phosphorylated myosin light chainssurrogate