Platelet antiserum inhibits hypoxic pulmonary vasoconstriction in the dog

Abstract

The literature suggests that platelets might help mediate the pulmonary vascular pressor response to hypoxia. The hypoxic response in dogs rendered acutely thrombocytopenic by the administration of platelet antiserum was studied. Between 30 and 90 min after the antiserum, the pulmonary vasoconstrictor response to hypoxia was virtually abolished but subsequently returned at a time when the number of circulating platelets remained very low. The prior administration of meclofenamate completely preserved the hypoxic response, though the platelet count still fell precipitously. Circulating platelets are apparently not necessary for hypoxic vasoconstriction. The reaction between platelets and antiserum may evoke the synthesis of a dilator prostaglandin which might be responsible for the temporary inhibition of the pressor response to hypoxia.