*3.7. Arterial Properties*

Endothelium-dependent ACh-induced vasodilatation in the aorta of female NTg mice was slightly higher than NTg males, whereas no sex-dependent differences were found in 3xTg-AD mice (Figure 8A). Sodium nitroprusside relaxations were not affected by sex, either in NTg or 3xTg-AD mice (Figure 8B). However, these relaxations were impaired (*p* < 0.05) in 3xTg-AD compared to NTg males. These results suggest an impairment of smooth muscle relaxing responses in 3xTg-AD males. We subsequently measured contractile responses to KCl (100 mM) (Figure 8C) and Phe (Figure 8D). Responses to KCl were significantly higher (*p* < 0.01) in the 3xTg-AD genotype in males but not females, an effect that culminated in greater (*p* < 0.05) contractions in 3xTg-AD males than females (Figure 8C). Nevertheless, concentration-dependent contractions to Phe were not affected either by sex or genotype (Figure 8D).

**Figure 8.** Influence of sex and genotype on aortic function. Concentration-dependent relaxations to acetylcholine (**A**) and sodium nitroprusside (**B**) in thoracic aortas from NTg and 3xTg-AD male and female mice. Contractions to KCL 100 mM (**C**) and concentration-dependent contractions to phenylephrine (**D**). Results are the mean ± SEM from NTg, male *n* = 7, female *n* = 5; 3xTg-AD, male *n* = 10, female *n* = 5. Data were analyzed by ×-way repeated measures (**A**,**B**,**D**) or regular (**C**) two-way ANOVA with Tukey post-test. \* *p* < 0.05, \*\* *p* < 0.01, # *p* < 0.05.
