Figure 1.
ACh-induced vasodilation in endothelium-intact mesenteric segments from control, breast-feeding (BF) and after BF rats. Results (mean±SEM) were expressed as a percentage of the previous tone elicited by exogenous NA. n = 6 animals each group.
Table 1.
Emax (%) and log EC50 (mmol/L) values of vasodilator responses to ACh in mesenteric arteries from control, BF and after BF female rats.
Figure 2.
Vasoconstrictor response to EFS.
EFS-induced vasoconstriction in endothelium-intact (A) and endothelium-removed (B) mesenteric segments from control, breast feeding (BF) and after BF rats. Results (Mean±S.E.M.) were expressed as a percentage of the initial contraction elicited by KCl. ANOVA P<0.05 Control vs. BF; ANOVA P<0.05 BF vs. After BF in both endothelium intact (A) and endothelium-removed (B) arteries. *P<0.05 vs. control animals at each frequency; #P<0.05 vs. BF group at each frequency (Bonferroni test). n = 10 animals each group.
Table 2.
EFS potentiation after endothelium removal.
Figure 3.
Effect of breast feeding on sympathetic innervation function.
Effect of preincubation with 1 µmol/L phentolamine or 1 µmol/L phentolamine plus 0.1 mmol/L suramin on the vasoconstrictor response induced by EFS in endothelium-denuded mesenteric segments from control (A) and breast-feeding (BF) rats (B). Results (Mean±S.E.M.) are expressed as a percentage of the previous contraction elicited by KCl. n = 6 animals each group. ANOVA P<0.05 vs. conditions without phentolamine in both experimental groups. *P<0.05 vs. conditions without phentolamine at each frequency (Bonferroni test). ANOVA P<0.05 phentolamine vs. phentolamine plus suramin in both experimental groups. # P<0.05 phentolamine vs. phentolamine plus suramin at each frequency (Bonferroni test). (C) Representation of remnant vasoconstriction after preincubation with 0.1 µmol/L phentolamine, expressed as area under curve (AUC). *P<0.05 control vs. BF. Differences of area under curve (dAUC) in the absence or presence of 01 µmol/L phentolamine (D) or in the absence or presence of 1 µmol/L phentolamine plus 0.1 mmol/L suramin (E). dAUC values are expressed as arbitrary units. *P<0.05 control vs. BF.
Figure 4.
Effect of breast feeding on NA vasoconstriction and release, and ATP release.
(A) Vasoconstrictor response to exogenous NA in segments from control and breast-feeding (BF) rats. Results (Mean±S.E.M.) are expressed as a percentage of the previous contraction elicited by KCl. n = 8 animals each group. (B) EFS-induced NA release in mesenteric segments from control and breast-feeding (BF) rats. Results (Mean±S.E.M.) are expressed as ng NA/mL mg tissue. n = 6 animals per group. (C) EFS-induced ATP release in mesenteric segments from control and breast-feeding (BF) rats. Results (Mean±S.E.M.) are expressed as mmol ATP/mL mg tissue. *P<0.05 vs control. n = 7 animals per group.
Table 3.
Emax (%) and log EC50 (mmo/L) values of vasoconstrictor response to NA or vasodilator response to DEA-NO in mesenteric arteries from control and BF rats.
Figure 5.
Effect of breast feeding on neuronal NO synthesis and vasodilation.
(A) EFS-induced NO release in segments from control and breast-feeding (BF) rats. Results (Mean±S.E.M.) are expressed as arbitrary units (A.U.)/mg tissue. *P<0.05 vs. Control; n = 8 animals per group. (B) Effect of breast feeding (BF) on nNOS and P-nNOS expression. The blot is representative of four separate segments from each group. Rat brain homogenates were used as positive control. Lower panel shows relation between P-nNOS or nNOS expression and ß-actin. Results (Mean±S.E.M.) are expressed as the ratio of the signal obtained for each protein and the signal obtained for ß-actin. *P<0.05 vs. control. (C) Vasodilator response to NO donor DEA-NO in segments from control and breast-feeding (BF) rats. Results (Mean±S.E.M.) are expressed as a percentage of the previous tone elicited by exogenous NA. n = 7 animals each group. (D) Superoxide anion release in mesenteric segments from control and breast-feeding (BF) rats. Results (Mean±S.E.M.) are expressed as chemiluminiscence units (U)/min mg tissue. n = 4 animals per group.
Figure 6.
Effect of breast feeding on nitrergic innervation.
Effect of preincubation with 0.1 mmol/L L-NAME on the vasoconstrictor response induced by EFS in mesenteric segments from control (A) and breast-feeding (BF) rats (B). Results (Mean±S.E.M.) are expressed as a percentage of the previous contraction elicited by KCl. n = 8 animals each group. ANOVA P<0.05 vs. conditions without L-NAME in both experimental groups. *P<0.05 vs. conditions without L-NAME for each frequency (Bonferroni test). (C) Differences of area under curve (dAUC) in the absence or presence of 01 µmol/L L-NAME. dAUC values are expressed as arbitrary units. *P<0.05.