Fig. 1

Percentage of dilating arterial segments and extension of vasodilation. a Percentage of dilating arterial segments compared to all the examined arteries. More arterial segments respond with vasodilatation when hypoxia becomes more severe. Under anoxia, 80% of all investigated arteries dilated. The dotted line may stress that the frequency of occurrence of dilatation was dependent from hypoxic oxygen concentrations. b Percentage changes of arterial vessel diameter under different hypoxic conditions in relation to the maximum vasodilatation using 0.1 mM nitroprusside sodium. n = number of arteries that responded to hypoxia with vasodilatation. Statistical testing was performed using the maximal evoked diameter using nitroprusside sodium as control. Student paired t test, Wilcoxon rank-sum test for non-parametric data (*p < 0.05)