REN and Hypertension: Present studies showed that stress-induced hypertension is of complicated pathogenesis which mainly involves the hypothalamus-pituitary-adrenal cortex (HPA) axis [3], sympathetic nerve-adrenal medulla (SAM) system [4], renin-angiotensin-aldosterone system (RAS) [5], NO/NOS system [6], and neuropeptide Y (NPY) [7].