Figure 5.

The mean concentration-dependent relaxation (black line and left scale) and the change in the frequency of the Ca²⁺ oscillations (gray line and right scale) induced by (A) (R,R)-formoterol (0–2,000 nM) and (B) racemic formoterol (0–4,000 nM) in airways contracted with MCh (400 nM). Numbers in parentheses indicate the equivalent (R,R)-formoterol concentration in racemic formoterol. Insets: the relationship between the reduction in Ca²⁺ oscillation frequency in SMCs and airway relaxation. As the concentration of (R,R)-formoterol or racemic formoterol increased, the relaxation increased and the Ca²⁺ oscillation frequency decreased (n = 4 mice for (R,R)-formoterol and racemic formoterol). Mean (±SD) values are presented; a minimum of three experiments was performed for each concentration for each mouse.