Ca ²⁺ oscillations triggered by 5-HT in individual smooth muscle cells from an intact mouse endothelium-denuded PA are potently inhibited by the inhibition of ANO1. All data were collected from the same PA from a conditional smooth muscle–specific and inducible GCaMP3 mouse injected with tamoxifen to induce Cre expression. (A) Ca²⁺ imaging was performed in the absence of an agonist (Control). The left panel shows one image from a video from which a ST map (middle colored image) was created in the area spanned by the diagonal white line. Fluorescence intensity was measured under the three white lines on the ST map (corresponding to two different cells) and plotted as a function of time as shown on the right. There was no detectable activity in these two cells as well as across the entire field of view of the movie. (B) Same nomenclature as in A except that the preparation was exposed to 1 μM 5-HT for 5 min. A ST map created in the same manner as that in A shows clear evidence of asynchronous Ca²⁺ transients. This is more evident from examining the fluorescence intensity profile of the same two cells analyzed in A, which displayed repetitive Ca²⁺ transient of distinct magnitude and frequency. (C) The nomenclature of this panel is identical to that of B and C, with the exception that the PA was exposed to 10 μM CaCC_Inh-A01 for 10 min while still being incubated with 5-HT. Examination of the ST map reveals little, if any, Ca²⁺ oscillations in the presence of the ANO1 inhibitor; Ca²⁺ transients were no longer apparent in the same two cells analyzed in A and B.