Effects of U46619 (10-7 M) and acetylcholine (Ach; 10-5 M), in the presence or absence of apamin (Ap, 5 × 10-7) plus charybdotoxin (Ch, 10-7 M), (Ap+Ch), on internal luminal diameter of airway and vessels in whole precision cut lung slices. Panel A shows responses in pulmonary artery and panel B shows responses in bronchi. Measurements were made under basal conditions or after stimulation with U46619 (U4; 10-7 M) or acetylcholine (Ach; 10-5 M) or U4, plus Ach in the presence of Ap plus Ch. The results are the mean +/- the S.E.M for n = 3 experiments. A p-value of < 0.05 was taken as statistically significant, calculated using ANOVA and denoted by *.