Effects of Pseudomonas aeruginosa endotoxin on vasodilation in the intact spinotrapezius muscle

Pseudomonas aeruginosa endotoxin on vasodilation in the intact spinotrapezius muscle. J Appl Physiol 91: 351–356, 2001.—The purpose of this study was to determine whether short-term exposure to clinically relevant concentrations of Pseudomonas aeruginosa lipopolysaccharide (LPS) impairs vasoreactivity of resistance arterioles in the intact spinotra-pezius muscle microcirculation and, if so, to determine the mechanisms mediating this response. Using intravital mi-croscopy, we found that 60-min suffusion of P. aeruginosa LPS (0.03–3.0 mg/ml) on the in situ hamster spinotrapezius muscle elicited an immediate, profound, and prolonged con-centration-dependent vasodilation (P, 0.05). This response was reversible once suffusion of P. aeruginosa LPS was stopped. Pretreatment with NG-nitro-L-arginine methyl ester (10.0 mM), a nonselective nitric oxide (NO) synthase inhibi