GJA5 and hypertensive disorder: 2009). Consequently, Cx40 knockout (Cx40KO) mice have a defective TGF mechanism, corresponding functionally to papillectomy (Sorensen et al. 2012). Preglomerular arterioles isolated from Cx40KO mice are unable to conduct a Ca2+ signal elicited by electrical stimulation (Sorensen et al. 2012). The lack of Cx40 also results in increased renin release and hypertension in these mice (Wagner et al. 2007).