Effects of epinephrine and norepinephrine on blood pressure of totally perfused dogs

A pump, capable of maintaining a constant flow output against pressure heads up to 200 mm Hg, has been utilized to completely replace the heart in dogs. Epinephrine and norepinephrine (0.5–10.0 µg/kg) were given in over 50 totally perfused animals. Comparable doses of these agents produced blood pressure responses essentially identical both in magnitude and character. Following adrenergic blockade by Dibenzyline, the pressor response to both epinephrine and norepinephrine was greatly reduced or abolished. The response to epinephrine after adrenergic blockade was quite often a depressor response. The depressor phase never occurred in response to norepinephrine. Sympathetic ganglionic blockade potentiated the pressure responses to both epinephrine and norepinephrine to approximately the same degree.