Superoxide anions mediate the effects of angiotensin (1-7) analog, alamandine, on blood pressure and sympathetic activity in the paraventricular nucleus

Publication date: Available online 11 June 2019Source: PeptidesAuthor(s): Juexiao Gong, Yihui Shen, Peng Li, Kun Zhao, Xuguan Chen, Yong Li, Yanhui Sheng, Bin Zhou, Xiangqing KongAbstractMicroinjection of alamandine into the hypothalamic paraventricular nucleus (PVN) increased blood pressure and enhanced sympathetic activity. The aim of this study was to determine if superoxide anions modulate alamandine’s effects in the PVN. Mean arterial pressure (MAP) and renal sympathetic nerve activity (RSNA) were recorded in anaesthetized normotensive Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHRs). Microinjection of alamandine into the PVN increased MAP and RSNA in both WKY rats and SHRs, although to a greater extent in SHRs. These effects were blocked by pretreatment with an alamandine receptor (MrgD) antagonist D-Pro7-Ang-(1-7). Pretreatment with superoxide anion scavengers, tempol and tiron, and NADPH oxidase inhibitor apocynin (APO), also blocked the effects of alamandine on MAP and RSNA. In addition, pretreatment in the PVN with a superoxide dismutase (SOD) inhibitor diethyldithiocarbamic acid (DETC) potentiated the increases of MAP and RSNA induced by alamandine administration, with a greater response observed in SHRs. Superoxide anions and NADPH oxidase levels in the PVN were higher in SHRs than that in WKY rats. Alamandine treatment increased the levels of superoxide anions and NADPH oxidase in WKY and SHRs, however, with greater effect in SHRs. These alama...
Source: Peptides - Category: Biochemistry Source Type: research