And, although a number of the classes of antihypertensive agents target the vascular smooth muscle [α-blockers, angiotensin converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), calcium channel blockers (CCBs)], until recently, there was little experimental evidence consistent with the regulation of vascular tone being an important factor for the molecular mechanism that produces hypertension (Fig. 1). The gene discussed is ACE; the disease is hypertensive disorder.