Fig. 6

9,11-dideoxy-9α,11α-methanoepoxy prostaglandin F_2α (U46619)-induced bronchoconstriction in long-term cultivated rat precision-cut lung slices (PCLS). PCLS with intact airways and surrounding epithelium were used in measurements of U46619-induced bronchoconstriction on measuring days. Different concentrations of U46619 (10^–10–10^–5 M) were added to the slice, constriction was measured via microscope. Images were analysed with ImageJ. For each timepoint, measurements were performed in duplicates, n = 4, the same slices were used for measurements with U46619 on every measuring day. Data is expressed as mean ± standard deviation (SD). First image of non-constricted airway of each measuring day was set as 100%. U46619-induced reduction of airway area was expressed as percentage of the initial airway area (%-IAA) (A). Using GraphPad Prism 9, nonlinear regression with a four-parameter logistic equation was conducted from data of U46619-induced bronchoconstriction (10^–10–10^–5 M). Maximal constriction (= efficacy) (B) and maximal airway area (C) were calculated. Analysis was performed based on control image of every measuring day ( ) and that of the first measuring day (●). Due to non-sigmoid characteristic, calculation of half-maximal response (EC₅₀) was not possible. Statistics were carried out using the general mixed model analysis (PROC GLIMMIX, SAS 9.4, SAS Institute Inc., Cary, NC, USA), statistical differences to day 1 are indicated by asterisks (*0.01 ≤ p < 0.05)