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Tobias Eckle, Almut Grenz, Stefanie Laucher, Holger K. Eltzschig
Published in Volume 118, Issue 10
J Clin Invest. 2008; 118(10):3301–3315 doi:10.1172/JCI34203
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Figure 4
cAMP levels and PKA activity during VILI.

(A and B) To assess cAMP levels and PKA activity in pulmonary tissues during VILI, A2BAR–/– mice and littermate controls were mechanically ventilated using pressure-controlled ventilation with an inspired oxygen concentration of 100% over 180 minutes at 45 mbar. Animals were euthanized, and lungs were perfused with 5 ml of PBS through the right ventricle. Lungs were excised, shock-frozen utilizing liquid nitrogen, and mechanically homogenized. cAMP levels (A) and PKA activity (B) were determined by ELISA. Note that the increases in cAMP and PKA activity associated with mechanical ventilation were abolished in A2BAR–/– mice. (C) Treatment with the specific β2-adrenergic agonist zinterol during VILI. Control C57BL/6 mice were treated with 300 μl 10–7 M intratracheal zinterol, and baseline cAMP levels were determined in lung homogenates using a competitive immunoassay kit. (D) Control C57BL/6 mice were treated with 300 μl 10–7 M intratracheal zinterol or vehicle control, followed by mechanical ventilation using pressure-controlled settings at an inspired oxygen concentration of 100% and 45 mbar inspiratory pressure for 0 or 180 min. Albumin concentration in the BAL fluid was determined by murine ELISA. (E) Survival times during VILI after 300 μl 10–7 M intratracheal zinterol or vehicle treatment. Mechanical ventilation was applied using pressure-controlled settings (inspiratory pressure of 35 mbar, inspired oxygen concentration 100%, respiratory rate and inspiratory/expiratory ratio were adjusted to maintain normal pH) until a cardiac standstill was observed in the surface electrocardiogram.