Fig. 7.

Left: representative tracings of mouse tracheal rings in wire myographs measuring force in grams. All treatment groups were precontracted with an EC₅₀ dose of ACh. The black bar labeled 405-nm light demonstrates the time course of blue-light treatments. The tracing labeled 0 μM was treated with 405-nm light alone. The other 3 tracings were pretreated for 1 h with 9-cis retinal at concentrations of 0.28, 2.8, and 28 μM, as indicated by their labeling. Tracings demonstrate a dose response to increasing 9-cis retinal pretreatments. Right: graphical analysis of mouse trachea rings during light treatments with varying 9-cis retinal pretreatments (0–28 μM) for a 1-h duration. Relaxation was measured as percent relaxation of the initial contraction. Pretreatments (9-cis retinal; 28 μM) had a significant 3-fold increase in relaxation versus blue-light treatment without 9-cis retinal pretreatment (*P < 0.01, n = 4–5). Furthermore, 28 μM 9-cis retinal pretreatment had a significant 2-fold increase in relaxation when compared with 0.28 μM 9-cis retinal pretreatment, demonstrating a dose response to 9-cis retinal pretreatments (#P < 0.05, n = 4–5 independent experiments with tracheal rings from 4 to 5 separate mice).