Norepinephrine Induces Lung Microvascular Endothelial Cell Death by NADPH Oxidase-Dependent Activation of Caspase-3

Figure 2

Norepinephrine activates Nox via α-adrenergic receptors. Rat lung microvascular endothelial cells (RLMEC) were stimulated with norepinephrine (NE) 5 ng/mL for 5 to 120 minutes. (a) NE increases Nox activity in RLMEC after 5 and 15 minutes of stimulation. (b) Representative images: NE increases p47phox phosphorylation at Ser370 in RLMEC after 15 minutes of incubation. (c) Quantification of p47phox phosphorylation in RLMEC stimulated or not with NE for 15 minutes: RFU (relative fluorescent units) is the ratio of fluorescence intensity/cell number of a given field in cells treated or not with NE. (d) Phentolamine (Phen), an antagonist of α₁-adrenoceptors, inhibits NE-induced Nox activation. (e) Propranolol (Prop), a nonspecific β-adrenoceptor antagonist, do not inhibit NE-induced Nox activation. vs. control; vs. NE; vs. prop. /group.

(a)

(b)

(c)

(d)

(e)