Effect of pregnancy on sympathetic innervation function.

Effect of preincubation with 1 μmol/L phentolamine on vasonstriction response induced by EFS in endothelium-denuded mesenteric segments from control (A) and pregnant rats (B). Results (mean±SEM) were expressed as a percentage of the initial contraction elicited by KCl. ANOVA P<0.05 vs. conditions without phentolamine in both experimental groups. *P<0.05 vs. conditions without phentolamine at each frequency (Bonferroni test). n = 8 animals per group. (C) Vasoconstriction response to NA in segments of control and pregnant rats. Results (mean±SEM) were expressed as a percentage of the initial contraction elicited by KCl. ANOVA P<0.05 Control vs. pregnant. *P<0.05 vs. control animals at each concentration (Bonferroni test). n = 8 animals per group. (D) EFS-induced NA release in mesenteric segments of control and pregnant rats. Results expressed as ng NA/mL mg tissue. *P<0.05 vs. Control. n = 6 animals per group.