Figure 3

Duration of acute CBF drop during SAH determines degree of delayed upregulation of contractile receptors in cerebral arteries. (A) Contractile responses induced by 63 mM K⁺ in middle cerebral arteries (MCA) and basilar arteries (BA) for sham-operated rats and SAH rats with short and prolonged acute CBF drops. Data are mean ± s.e.m. of maximal K⁺-induced contractions for each vessel segment. (B and C) Concentration-contraction curves for basilar arteries stimulated with cumulative doses of ET-1 (B) or 5-CT (C). Shown are data obtained at 3 days after surgery in sham-operated rats, SAH-induced rats with short acute CBF drop and SAH-induced rats with prolonged acute CBF drops. Data are mean ± s.e.m as percent of 63 mM K⁺-induced contraction. Stars indicate significant differences between sham and SAH-induced animals as determined by two-way ANOVA (***: p < 0.001). Crosses indicate significant differences between SAH-induced rats with short and prolonged acute CBF drop, respectively, as determined by two-way ANOVA (+++: p < 0.001).