FIGURE 4.

A cyclopiazonic acid-insensitive sarcoplasmic reticulum Ca²⁺ store underpins Ca²⁺ signaling in response to ET-1 in pulmonary arterial smooth muscle cells. A–C, the effect on the Fura-2 fluorescence ratio (F₃₄₀/F₃₈₀) in the absence (A) and presence of cyclopiazonic acid (B) and thapsigargin (C). D, bar chart shows the means ± S.E. for the percentage change in Fura-2 fluorescence ratio induced by ET-1 in the absence and presence of cyclopiazonic acid (CPA) and thapsigargin (Thapsi), respectively.