Fig. 1.

Relaxation of pulmonary veins of normoxic and chronically hypoxic fetal lambs induced by 8-bromoguanosine 3′,5′-cyclic monophosphate (8-Br-cGMP). Vessels were preconstricted with endothelin-1 (6 × 10⁻⁹ to 10⁻⁸ M). PKG-I, Rp-8-Br-PET-cGMPS, β-phenyl-1,N²-etheno-8-bromoguanosine 3′,5′-cyclic monophosphorothioate, Rp isomer, 3 × 10⁻⁵ M. Y-27632, 10⁻⁵ M. Data are shown as means ± SE; n = 6–8 for each group. *Significant difference between normoxic and chronically hypoxic vessels; †significant difference between control and vessels treated with PKG-I (left) or Y-27632 (right) (P < 0.05).