Fig. 3.

Ca²⁺ pulsars originating from IP₃-sensitive stores. Removal of extracellular Ca²⁺ (A) or ryanodine (C) did not affect Ca²⁺ pulsars. Inhibition of SERCA with CPA (B), of IP₃Rs with xestospongin C (D), or of PLC with U73122 (E) decreased Ca²⁺ pulsars. (F) A data summary of pharmacological experiments targeting the source of Ca²⁺ pulsars is given. (n = 6, 5, 4, 6, and 3 arteries for 0 Ca²⁺, CPA, ryanodine, xestospongin C, and U73122, respectively; *, P < 0.05). For A–E, different colors represent F/F_o in ROIs over different pulsar sites in the endothelium. Calcium pulsars were recorded for 2 min, followed by variable incubation times (0 Ca, 5 min; Ry, 35 min; CPA, 15 min; xestospongin C, 40 min; U73122, 15 min) and then 2 min of recording in the drug treatment (see Methods Summary).