Inhibition of Src family tyrosine kinases prevents lipopolysaccharide-induced hyporeactivity in isolated rat tail arteries

Abstract Tyrosine kinases may play a role in the vascular response to sepsis. We investigated the effect of selective inhibitors of Src family tyrosine kinases (SFK) on lipopolysaccharide (LPS)-induced vascular hyporeactivity. Rat tail artery segments were mounted in an isometric wire myograph. The effect of incubation with LPS was examined on phenylephrine (PE) and high potassium (KPSS)-induced contraction, with and without the selective SFK inhibitors SU6656 or PP1. Western blotting was performed to assess SFK phosphorylation and iNOS induction. Incubation with LPS for 18 h induced marked vascular hyporeactivity to both PE ( p < 0.001) and KPSS ( P < 0.001). Incubation with SU6656 alone had no effect on contractility to PE and KPSS, and SU6656 partially prevented LPS-induced hyporeactivity to PE ( p < 0.01) and KPSS ( p < 0.001). In contrast, PP1 alone diminished contractility to PE ( p < 0.01) and KPSS ( p < 0.001), and co-incubation of LPS with PP1 completely prevented LPS-induced hyporeactivity. LPS increased tyrosine phosphorylation of SFK and this effect was inhibited by SFK inhibitors. LPS also increased levels of iNOS and this was also inhibited by SU6656 and PP1. LPS-induced hyporeactivity in vitro is mediated by activation of SFK. Selective inhibitors of SFK may have therapeutic potential in the management of septic shock.