Effects of peptides on blood pressure and heart rate in rats. Rats were sedated and catheterized for administration of drugs and measurement of hemodynamic parameters as described in the text. At the indicated times the following actions were taken: administration of saline to ensure that the animal and intubations were stable; administration of enoxaparin; administration of test peptide (or protamine alone); and administration of protamine following nonresponse to peptide. Systolic and diastolic blood pressure are shown. This pair of graphs demonstrates the absence of blood pressure changes after administration of 1 mg/300 g rat of (ARKKAAKA)3VLVLVLVL in the presence and absence of enoxaparin. Other animals given this peptide had been observed to have stable blood pressure when monitored for 30 minutes with no subsequent protamine administration. Upper curve: systolic pressure. Lower curve: diastolic pressure. The results with animals treated with each peptide are summarized in the text.
