Figure 2. Ventilatory response ( ${\dot{V}}_{\mathrm{E}}$ ; expressed as the percentage change) to hypercapnia .

The percentage change of ${\dot{V}}_{\mathrm{E}}$ in normoxic hypercapnia with almorexant (Amxt) treatment (hatched bars) and without (black bars) in young and adult SHRs vs. that in normotensive young and adult WKY rats (grey bars). Value are shown as means + SEM. ^*Values are significantly different with Holm–Sidak or Student–Newman–Keuls post hoc test (P < 0.05–0.001).