Nitric Oxide Synthase Enzymes in the Airways of Mice Exposed to Ovalbumin: NOS2 Expression Is NOS3 Dependent

Figure 5

Total lung resistance in (a) C57BL/6, (b) NOS1${}^{-/-}$, (C) NOS2${}^{-/-}$, and (D) NOS3${}^{-/-}$ mice exposed to either filtered air or 2 weeks of OVA. Symbols: (blue) open triangles for filtered air exposure, (black) circles for OVA exposure. Lung resistance was measured at baseline and following serial doses (0.5–2.0 mg/mL) of nebulized methacholine. NOS1${}^{-/-}$ mice exposed to OVA (slope = $0.266\pm 0.027\text{,}$$F=94.09$) had a significantly greater increase in lung resistance compared to the same strain of mice exposed to filtered air (slope = $0.079\pm 0.008\text{,}$$F=93.15\text{;}$$P=.002$). Air- and OVA-exposed NOS2${}^{-/-}$ mice had similar increases in lung resistance (slopes = $0.12\pm 0.01$ and $.015\pm 0.02$, resp.), but their intercepts were significantly different ($y$ intercept $1.09\pm 0.02$ versus $1.3\pm .0.06$, resp., $P=.0001$).

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