Figure 5
From: The dopamine D1receptor is expressed and facilitates relaxation in airway smooth muscle
Dopamine induced airway smooth muscle relaxation after an acetylcholine EC 50 contraction in intact guinea pig trachea. Dopamine, in a concentration-dependent manner, relaxes acetylcholine (Ach)-induced contractions in guinea pig tracheal rings. (A) Representative tension tracing in guinea pig tracheal ring illustrating relaxation of Ach (EC50) contraction by dopamine (1 - 100 μM). (B) The effect of cumulative concentration of dopamine (1 - 100 μM) on Ach (EC50)-induced guinea pig tracheal ring contraction. Open circles: dopamine alone. Filled circles: time control. Means ± SEM. *P < 0.05 and **P < 0.01 compared with time control. N = 5.