Figure 5.

The effect of FSK and 8-bromo-cAMP on contraction and Ca²⁺ oscillations of airway SMCs. (A) FSK (10 μM, solid line) and (D) 8-bromo-cAMP (500 μM, solid line) induced an initial quick relaxation followed by slower relaxation. (B) FSK and (E) 8-bromo-cAMP decreased the Ca²⁺ oscillation frequency initiated by MCh to a slower rate. The changes in the frequency of the Ca²⁺ oscillations induced by each compound (dotted line in A and D) correspond with opposite changes in airway area (solid line in A and D). (C) With increasing FSK concentration, the relaxation (solid line, ■) increased while the frequency of the Ca²⁺ oscillations (dotted line, ▼) decreased; each point is the mean ± S.E. from at least 4 different airways from 3 mice. Data points were fitted with a logistic function.