Depression of hypoxic pulmonary vasoconstriction in the dog by dopamine and isoprenaline

The effects of dopamine and isoprenaline on the pulmonary vasoconstrictor response to alveolar hypoxia were assessed by measuring the redistribution of blood flow between the lungs in response to unilateral hypoxia. Dose rates of dopamine 25 micrograms kg-1 min-1 and isoprenaline 0.25 micrograms kg-1 min-1 (which produced equal increments in thecontractile force of the heart in dogs) produced a similar degree of depression of they hypoxic vasoconstrictor response, whereas dopamine 2.5 micrograms kg-1 min-1 had little effect on the response PaO2 during unilateral hypoxia was inversely related to the blood flow through the hypoxic lung.