Objective To explore the effect of calcitonin gene-related peptide(CGRP) and ET_1 on hypertension.Methods 42 rats with normal blood pressure were randomly divided into operation,sham operation and control groups.The level of CGRP and ET_1 were determined at 2,4,6,8 and 10 weeks after treatment,respectively.Results The blood pressure in rats of the operation group was significantly higher than that in the control group(P<0.01),but there was not significant difference between that of rats in the sham operation and normal control groups.CGRP of the operation group was significantly higher than that of control group(P<0.05).ET_1 of the operation group was significantly higher than that of control group.No significant difference was found between the ET_1 and CGRP in the sham operation group and control group.Conclusion CGRP has a protective effect on blood vessels in renal arterial hypertension,but ET_1 exerts a vasoconstrictive action.