The effect of estrogen and a high salt diet on arteriolar reactivity to increased tissue oxygen in the spinotrapezius muscle of the female SS rat

Abstract

Estrogen may protect against salt induced microvascular dysfunction. Female SS (Dahl Salt Sensitive, SS/JrHsdMcwi) were divided into 2 subgroups: ovariectomized with (OVX +E) or without (OVX‐E) estrogen replacement. Three days prior to the acute experiment the diet of half of the rats was changed from low salt (LS, 0.4% NaCl) to high salt (HS, 8.0% NaCl). On the day of the acute experiment a transverse arteriole in the spinotrapezius muscle was selected, allowed to equilibrate with 0% O2 in the superfusion solution, and then changes in arteriolar diameter to 21% O2 in the superfusion solution before and after the topical application of HET‐0016 (10μM), a selective inhibitor of 20‐HETE production, were measured. Neither estrogen nor HS affected arteriolar constriction to 21% O2. HET‐0016 significantly attenuated arteriolar constriction to 21% O2 in the SS rat with or without estrogen and on a LS diet. However, the inhibition was greater in the SS rat without estrogen. HET‐0016 did not significantly inhibit the oxygen induced arteriolar constriction in the SS rat with or without estrogen and on a HS diet. These results suggest that a HS diet and estrogen reduce the contribution of 20‐HETE to oxygen induced arteriolar constriction in the spinotrapezius muscle. Funded by an internal UW‐M Research Growth Initiative grant.