Figure 3: Tracheal responsiveness to MCh in AIRmin or AIRmax mice. Tracheal responsiveness of AIRmin or AIRmax to inhaled MCh was evaluated in the absence (a) or presence (b and c) of gallamine. Mouse tracheal segments were cultured in PBS or with gallamine for 20 min. Thereafter, the segments were maintained in the organ bath, and the contractile responses to MCh were recorded. Data are expressed as mean ± SEM of six mice per group * .