SLC9A3 and Hypertension: However, there is evidence that the expression and activity of NHE3 in the proximal tubules are decreased rather than increased in the development of hypertension in SHRs, and therefore NHE3 unlikely plays an important role in the development of spontaneous hypertension (Yip et al., 1998; Magyar et al., 2000; Panico et al., 2009; Crajoinas et al., 2014).