Reduction of bovine pulmonary hypertension by normoxia,verapamil and hexaprenaline

Summary In calves with hypoxic pulmonary hypertension, resistance was reduced by 40±3% with normoxia, 19±4% with verapamil, and 60±1% with hexoprenaline. It is possible that the increased resistance during normoxia is due partly to vasoconstriction rather than solely to vascular thickening, and that the vasoconstriction is due to an abnormality in calcium metabolism by the hypertensive vasculature.Acknowledgments. We thank Rosann Glas, Mary Munroe, Diann Smith and Linda Panepinto for technical assistance. This work was supported by the Colorado Heart Association and by the National Institutes of Health Grants HL-05973 and HL-29237. Verapamil (Isoptin) was supplied by Knoll Pharmaceutical Co. Hexoprenaline (ST 1512 HCl, Ipradol) was supplied by Österreichische Stickstoffwerke Linz.