Fig. 3. Comparison of the positive inotropic effects of α-adrenergic stimulation in control conditions (pH = 7.40, n = 8) and in metabolic (pH = 7.10, n = 8) or respiratory acidosis (pH = 7.10, n = 8) in isotonic (A ) and isometric (B ) conditions. Data are mean ± SD. AF = isometric active force normalized for cross-sectional area; NS = not significant; Vmax= maximum unloaded shortening velocity. P values refer to the between group comparison of the maximum effect (see table 3).