The present invention provides for novel kinin B1 receptors peptide agonists of formula (I) having very good to excellent affinities and selectivity for the B1 receptor, in vitro and in vivo increased resistance to enzymatic degradation, superior pharmacokinetic properties to those of naturally occurring agents, capacity to significantly enhance delivery of chemotherapeutic substances across the blood brain barrier and within peripheral tissues for the treatment of tumors, capacity to protect and restore kidney, heart, brain and other organ functions, when given alone or in combination with other therapies in the treatment of hypertension, diabetes and other cardiovascular diseases particularly, but not limited to, atherosclerosis and arteriosclerosis. Formula (I): aay-aax-aa0-aa1-aa2-aa3-aa4-aa5-Ser6-Pro7-D-Phe8-X.