Fig. 3

Inhibition of BK channels with iberiotoxin or inhibition of Ca²⁺ sparks with tetracaine does not increase the global [Ca²⁺]_i or constrict the SMA at 40 cmH₂O. a Representative recordings of [Ca²⁺]_i changes from single smooth muscle cells from a pressurized (40 cmH₂O) SMA in response to 100 nM Ibtx. b Average of normalized traces of [Ca²⁺]_i changes in the presence of Ibtx (65 cells). Traces in a and b were normalized as described in Methods. c Average trace of corresponding changes in vascular diameter in the presence of Ibtx (8 arteries). d Representative recordings of [Ca²⁺]_i changes from single smooth muscle cells from a pressurized (40 cmH₂O) SMA in response to 100 μM Tet and 1 μM nifedipine (Nif). e Average of normalized traces of [Ca²⁺]_i changes at 40 cmH₂O (26 cells). Traces in d and e were normalized as described in Methods. f Average trace of corresponding changes in vascular diameter (5 arteries) in the presence of Tet and Nif. Diameter changes were normalized to the average of values recorded between 30–60s (value indicated by ‘a’ was set to 1). [Ca²⁺]_i and diameter data were simultaneously acquired at 1 s intervals, however, for clarity, error bars (sem) are plotted only every 10s