Fig. 2. Representative recordings of the application of midazolam (A ), and halothane (B ) on acetylcholine-induced Ca²⁺sensitization in β-escin–permeabilized canine tracheal smooth muscle. Muscarinic receptor stimulation with 10 μM acetylcholine (ACh) plus 10 μM guanosine 5′-triphosphate (GTP) increased force during exposure to 0.3 μM Ca²⁺(indicating an increase in Ca²⁺sensitivity). Note that halothane, but not midazolam, decreased calcium sensitivity.