Statistical Analysis
Histograms and q-q plots were used to evaluate the assumption of normality. Continuous data were presented as mean (SD). The independent samples Student’s t-test was used to evaluate the differences between two groups, whilst the one-way ANOVA was used to evaluate differences among >2 experimental groups followed by Tukey’s multiple comparisons test. To examine the effect of genotype on tension over extended U46619 concentrations we fitted mixed-effects models, implementing the restriction maximum likelihood estimation, with random intercepts for the different mice. Interactions of the genotype with the different levels of concentration were tested. To decide upon the inclusion of the interaction term we used the Bayesian information criterion (BIC). The interaction term was kept in the model if it produced a smaller BIC value compared to a model with no interaction term. For the models with the interaction term this meant that the genotype effect on vessel tension was not always constant, therefore it varied according to the levels of the U46619 concentration (i.e., dependent of vasoconstrictor concentration: Fig. 5C, 6A, 6B, 6C & 6D). For the models with no interaction term this meant that the genotype effect on vessel tension was independent on the vasoconstrictor concentration (Fig. 5A, 5B, 5D & SF. 10 E). Point estimates are stated in text, whilst the 95% confidence intervals (95% CI) are plotted in the relevant figures. In all analyses, the significance level was set at 5%. Data were analysed using Prism software (GraphPad version 8.1.2., GraphPad Software Inc.) and Stata 16 (StataCorp, 2019. Stata Statistical Software: Release 16. College Station, TX: StataCorp LLC.).