Treatment of Renal Artery Rings and Myography:
The following treatment method was performed as previously described
(Durgin, et al., 2019). In brief, murine renal arteries were rapidly
cleaned, excised, cut into 2 mm rings, and placed in room temperature
physiological salt solution (PSS) which contains: 119 mM NaCl, 4.7 mM
KCl, 1.17mM MgSO4, 1.18 mM KH2PO4, 5.5
mM D-glucose, 25 mM NaHCO3, 0.027 mM EDTA, and 2.5 mM
CaCl2. Rings were then placed on a small vessel wire
myograph (DMT 620M) filled with PSS (pH 7.4 when bubbled with 95%
O2 5% CO2 at 37°). Following a 30
minute rest, arteries were then gradually stretched to a tension
corresponding to a transmural pressure of 80 mmHg. Arteries were then
constricted with a dose response of phenylephrine (50 nM - 50 mM). Rings
were washed 3 times with PSS and allowed to rest for 30 minutes. A final
wash was performed, and arteries were rested for an additional 10
minutes. Following the final 10 minute rest period, arteries were
constricted with a single dose of phenylephrine (1 mM). After reaching a
plateau, a continuous dose response curve to ACh (10 µM-10 mM, Sigma,
MA6625) or sodium nitroprusside (SNP; 1 nM-10 mM, Sigma, 71778) was
administered to assess endothelium-dependent and NO-dependent
relaxation, respectively. Maximal dilatory responses were subsequently
determined using 100 μM SNP in Ca2+-free PSS. The
percentage relaxation reported represents the data normalized to the
maximal dilation by 100 μM SNP in Ca2+-free PSS in
phenylephrine-constricted vessels.