Physiological Salt Solution Tension Assay

As described in our previous publication (Shi et al., 2020 (link); Li et al., 2023 (link); Peng et al., 2023 (link)), physiological salt solution (PSS) was prepared for tension measurement. Trachea and lung tissue were removed from euthanized mice and quickly transferred to ice-cold PSS. Then 6 mm mTRs were excised and suspended in a 6 mL organ bath filled with PSS at 37°C. After a 60 min equilibration (fresh PSS was refilled every 15 min), high K⁺ (80 mM) or ACh (100 μM) was employed to evoke a successive precontraction on each mTR. Then, tension measurements were conducted. According to the experiments, vandetanib or certain ion channel inhibitors were added to the organ bath. In the study of NCX, 135 mM NaCl was replaced with 135 mM LiCl.