Stimulation of Epithelial Sodium Channels in Endothelial Cells by Bone Morphogenetic Protein-4 Contributes to Salt-Sensitive Hypertension in Rats

Figure 3

HS diet impairs EDR and stimulates ENaC via a pathway associated with BMP4 in SS rats. (a) Representative traces of ACh-induced artery relaxation in NS or HS diet-fed SS rats; the vascular rings were, respectively, treated with BMP4 (50 ng/mL) and noggin (200 ng/mL) for 4 hours and benzamil (1 μM) for 1 hour before experiments. The first dot in each plot represents the time when Phe (10 μM) was added. The following dots indicate ACh concentrations gradually increased to 0.1 nM, 1 nM, 10 nM, 100 nM, 1 μM, 10 μM, and 100 μM. (b) Summary of relaxation responses of mesenteric arteries to different doses of ACh under the conditions shown in (a). indicates vs. NS; ^#indicates vs. HS; ^&represents vs. NS + BMP4 ( for each group). (c) Summary of relaxation responses of mesenteric arteries from these rats to different doses of NTG ( for each group). (d) Representative ENaC single-channel currents in intact endothelial cells attached to a mesenteric artery isolated from NS or HS diet-fed SS rats; mesenteric arteries, respectively, treated with BMP4 (50 ng/mL) and noggin (200 ng/mL) for 4 hours and application of 1 μM benzamil prior to recording. (e) Summary of ENaC P_O obtained from different experimental groups as shown in (d). vs. NS, ^#vs. HS, ^&vs. NS + BMP4 ( rats for each group). (f–g) Representative perforated whole-cell recording setup and summarized data showing the ENaC currents in primary cultured endothelial cells isolated from SS rats. The cells were cultured with or without an additional 20 ng/mL BMP4 in the culture medium for 24 hours, in the presence or absence of 1 μM benzamil. indicates vs. control group; ^#represents vs. BMP4 treated group ( individual cells for each group).

(a)

(b)

(c)

(d)

(e)

(f)

(g)