The percentage of apoptotic cells was assayed with APOPercentage Apoptosis Assay according to manufacturer's instructions (Biocolor Life Science Assays). Photographs were taken with an Olympus DP70 Digital microscope camera connected to an Olympus IX71 light microscope using DP Controller (version 2.2.1.227) and DP Manager (version 2.2.1.195) softwares. The stained (apoptotic) and unstained cells were manually counted, and the percentage of apoptotic cells was calculated.  Angiotensin-Converting Enzyme 2: Central Regulator for Cardiovascular Function Angiotensin-converting enzyme 2 (ACE2) is a new component of the renin-angiotensin system (RAS). Accumulating evidence shows that ACE2 provides protective effects in peripheral tissues and has great potential for the treatment of RAS-related diseases. The role of ACE2 in the central nervous system is not well established. However, in recent years, much more progress has been made on the studies of this carboxypeptidase in the central regulation of blood pressure and cardiovascular function in general. It has been shown that brain ACE2 interacts with the other components of the RAS (ACE, angiotensin II, and angiotensin II type 1 receptor), protects baroreflex and autonomic function, stimulates nitric oxide release, reduces oxidative stress, and prevents the development of or attenuates hypertension. These data support the critical role of ACE2 in the central regulation of cardiovascular function. This review summarizes recently published data on the central effects of ACE2 in the regulation of cardiovascular function. The renin-angiotensin system (RAS) plays a regulatory role in cardiovascular function and a pathogenic role in the development of hypertension and associated cardiovascular disorders. In addition to the classic endocrine system, local RASs are present in various tissues throughout the body, interacting with each other and the endocrine RAS.