Fig. 8.
Benzbromarone (Benzb) and N-((4-methoxy)-2-naphthyl)-5-nitroanthranilic acid (MONNA) attenuate sarcoplasmic reticulum (SR) calcium release in human airway smooth muscle cells. (A) Representative tracing of calcium imaging using fura-2 and mag-fluo-4. Cells were pretreated with vehicle (0.1% dimethyl sulfoxide [DMSO]) or 1 μM thapsigargin, and then 10 μM bradykinin. Thapsigargin treatment caused a leak of calcium from the SR, represented by a decrease in fluorescence of mag-fluo-4 and increase in fura-2 fluorescence. (B) Representative tracing demonstrating attenuation of SR calcium release with 50 μM Benzb treatment. With control vehicle (0.1% DMSO) pretreatment, bradykinin causes a decrease in mag-fluo-4 fluorescence and increase in fura-2, whereas pretreatment with 50 μM Benzb attenuates these changes. (C, E) Pretreatment with Benzb (10 and 50 μM) or MONNA (10 and 50 μM) showed an attenuation of increases in intracellular calcium induced by 10 μM bradykinin (C) (**P < 0.01, ***P < 0.001, n = 10 DMSO, n = 15 Benzb and MONNA) or 10 μM acetylcholine (Ach) (E) (***P < 0.001, n = 6 DMSO, n = 8 Benzb and MONNA) when compared to vehicle control. (D, F) Pretreatment with Benzb (10 and 50 μM) or MONNA (10 and 50 μM) showed an attenuation of decreases in SR calcium induced by 10 μM bradykinin (D) (*P < 0.05, **P < 0.01, ***P < 0.001, n = 10 DMSO, n = 15 Benzb and MONNA) or 10 μM Ach (F) (*P < 0.05, ***P < 0.001, n = 6 DMSO, n = 8 Benzb and MONNA) when compared with vehicle control.