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. 2008 Sep 5;295(5):L915–L924. doi: 10.1152/ajplung.90286.2008

Fig. 2.

Fig. 2.

Calcium-dependent resting tone is elevated in isolated lungs of 21-day CH compared with N piglets. A: resting transpulmonary pressures (ΔPtp) of 11.62 ± 0.82 mmHg in lungs of N piglets (n = 4) was reduced by 1.87 ± 0.24 mmHg by nifedipine (NIF; 10 μmol/l) and an additional 4.00 ± 0.41 mmHg by papaverine (Papav; 15-mg bolus). Thus L-type Ca2+ (CaL) channels accounted for 32% of active tone sensitive to papaverine. B: nifedipine had a more pronounced attenuating effect on the elevated resting ΔPtp of 20.50 ± 2.09 mmHg in lungs of CH piglets (n = 5). In these lungs, nifedipine reduced ΔPtp by 6.40 ± 1.35 mmHg, and papaverine lowered ΔPtp an additional 3.70 ± 0.81 mmHg. Thus 62% of the elevated ΔPtp sensitive to papaverine was dependent on Ca2+ influx through CaL channels. *Significantly different (P < 0.05) from control (Con) ΔPtp in the same preparation.