Figure 5.

A, Coexpression of Sk1^wt with the phosphatase-dead SPP1^H208A resulted in enhanced myogenic vasoconstriction (n=5), compared to the control responses presented in B. Vessels coexpressing Sk1^wt/SPP1^wt displayed significantly weaker myogenic responses (n=7). B, Shown is the constriction of depolarized resistance arteries (120 mmol/L K⁺) in response to increasing extracellular Ca²⁺ (Ca²⁺ex from 0 to 3 mmol/L). Vasoconstriction in vessels coexpressing Sk1^wt/SPP1^wt (n=7) was significantly greater at 0.25 and 0.50 mmol/L Ca²⁺ex, compared to vessels coexpressing Sk1^wt/SPP1^H208A (n=5). C, Sphingosine-1-phosphate–induced constriction was significantly attenuated in resistance arteries coexpressing Sk1^wt/SPP1^wt (n=5), compared to vessels coexpressing Sk1^wt/SPP1^H208A (n=7). *P<0.05 compared to vessels coexpressing Sk1^wt/SPP1^H208A.