Abstract: AIM:To examine the effect of endoplasmic reticulum stress (ERS) on vascular remodeling induced by hypertension and to observe the effects of enalapril on the expressions of the correlation factors GRP78 and caspase-12 in vascular smooth muscle cells (VSMCs) and their relationship with vascular changes. METHODS: Forty adult male SD rats were randomly divided into sham operation group, sham+Ena group, AAB group and the AAB+Ena group. Four weeks later, MBP was measured through carotid artery incubation, the aortic media thickness was measured by image analyses software and the expressions of GRP78 and caspase-12 in the vascular smooth muscle cells were examined by immunohistochemistry. RESULTS: MAP of AAB group rats was significantly higher than those of rats in sham operation group, sham+Ena group and AAB+Ena group (P<0.05). The aortic media thickness of AAB group rats was significantly thicker than those of rats in sham operation group, sham+Ena group and the AAB+Ena group (P<0.05). The expressions of GRP78 and caspase-12 of AAB group rats were significantly higher than those of rats in sham group, sham+Ena group and AAB+Ena group. CONCLUSION: High blood pressure resulting from abdominal aortic bounding causes endoplasmic reticulum stress response of vascular smooth muscle cells. Enalapril may exert some protective effects on VSMCs by inhibiting the endoplasmic reticulum stress via downregulation of the expression of caspase-12.