Enhancement of Methacholine-Evoked Tracheal Contraction Induced by Bacterial Lipopolysaccharides Depends on Epithelium and Tumor Necrosis Factor

Figure 1

LPS administration increases basal and methacholine-induced respiratory patterns but not airway resistance. Respiratory parameters were determined in C57BL/6 mice by noninvasive (Buxco apparatus) or invasive (FlexiVent apparatus) barometric plethysmography. Penh values or resistance were used as index of the respiratory parameters obtained before (a and c) and after (b and d) sequential delivery of increasing concentrations of methacholine 24 h after instillation of PBS (open circles) or LPS (filled circles). Results are reported as Penh values (a and b) or resistance (c and d). Penh data represent the means ± SEM of five mice per group and resistance data represent the means ± SEM of three to five mice per group (unpaired t-test, *𝑃<0.05, **𝑃<0.01 as compared to control).

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